Shared Channels & Cross-Tenant Access | Guided by A Guide to Cloud

Beyond guest access

Simple explanation

Guest access is like giving someone a visitor badge to your building. It works, but they’re always marked as “visitor” and they have to log into YOUR systems.

Shared channels are more like having a meeting room between two buildings — both companies can walk in from their own side. External users stay in their own tenant, use their own identity, and see the shared channel right inside their own Teams client. No switching tenants, no guest accounts.

Multi-tenant organisations (MTO) go even further — they make two separate tenants behave almost like one. Users across tenants can search each other, see presence, and collaborate as if they were in the same company.

Shared channels — how they work

Shared channels enable cross-tenant collaboration without guest accounts:

Feature	Standard Channel	Private Channel	Shared Channel
Membership	All team members	Invited team members only	Anyone — including external users from other tenants
External users	Need guest account	Need guest account	NO guest account needed (B2B direct connect)
SharePoint site	Team’s main SharePoint site	Separate SharePoint site	Separate SharePoint site
Where it appears	In the host team	In the host team	In the host team AND in external users’ Teams client
Identity	Host tenant identity	Host tenant identity	HOME tenant identity (no tenant switching)

Shared channel limitations (exam-critical)

Shared channels have notable limitations compared to guest access:

Up to 1,000 shared channels per team (within total channel limit)
No bots, connectors, or message extensions in shared channels (tabs are supported except Stream, Planner, and Forms)
No @team mentions — only @channel and @user
No scheduled channel meetings — only ad-hoc meetings
Private channels can’t become shared — only standard team channels can be shared
Both tenants must configure B2B direct connect — it’s not unilateral

Exam tip: Guest access vs. shared channels — when to use which

A common exam pattern asks you to choose between guest access and shared channels:

Use guest access when: external users need apps, bots, tabs, or full team membership. Guest access gives more features but requires a guest account.
Use shared channels when: you want seamless cross-tenant collaboration with no tenant switching, no guest accounts, and the collaboration fits within channel limitations. Best for focused project collaboration.
Use external access (federation) when: you only need 1:1 chat and calls with no file sharing or team content access.

Configuring B2B direct connect

Shared channels require B2B direct connect in both tenants. Configuration in Entra ID → External identities → Cross-tenant access settings.

Both tenants must configure

In the resource tenant (hosting the shared channel):

Add the partner organisation (by tenant ID or domain)
Inbound access → B2B direct connect → Allow users from the partner to access shared channels
Configure which users/groups from the partner are allowed

In the home tenant (where external users live):

Add the partner organisation
Outbound access → B2B direct connect → Allow your users to access shared channels in the partner tenant
Configure which of your users can participate

Both inbound AND outbound must be configured. If Pinnacle Corp allows inbound from Partner Corp, but Partner Corp doesn’t allow outbound to Pinnacle Corp, shared channel access fails.

Scenario: Tara configures shared channels for APAC partners

Pinnacle Corp (Melbourne) collaborates with two APAC partners on a joint project. Tara configures B2B direct connect:

Pinnacle Corp (resource tenant — hosts the shared channel):

Adds Partner-Tokyo (tenant ID) → inbound B2B direct connect → Allow all users
Adds Partner-Singapore (tenant ID) → inbound B2B direct connect → Allow “Project Team” group only

Partner-Tokyo (home tenant):

Adds Pinnacle Corp → outbound B2B direct connect → Allow all users

Partner-Singapore (home tenant):

Adds Pinnacle Corp → outbound B2B direct connect → Allow “Joint Venture” group only

Tara creates a shared channel “#apac-joint-project” in the existing “Infrastructure” team. She adds users from Tokyo and Singapore. Those users see the channel appear directly in their own Teams client — no tenant switching needed.

Multi-tenant organisations (MTO)

MTO is designed for enterprises with multiple Entra ID tenants — typically from mergers, acquisitions, or regional structures.

What MTO enables

Capability	Without MTO	With MTO
People search	Users can’t find people in other tenants	Cross-tenant people search works
Presence	External users show as “Unknown”	Real-time presence visible across tenants
1:1 chat	Works via external access (federation)	Seamless — feels like same org
Profile cards	Limited info for external users	Full profile info across tenants

MTO configuration

Define the MTO in Entra ID → one tenant is the “owner” tenant
Add member tenants via the owner tenant
Member tenants accept the MTO invitation
Cross-tenant sync automatically provisions users across tenants
Shared email domain (optional) for a unified address book

Licensing: MTO requires Microsoft Entra ID P1 or higher in all participating tenants.

Scenario: Pinnacle Corp's post-acquisition MTO

Pinnacle Corp acquired a NZ company. Both have separate Entra ID tenants:

pinnacle.com.au (2,000 users)
acquired-nz.co.nz (500 users)

Instead of migrating all NZ users into the AU tenant (risky and disruptive), Tara configures an MTO:

pinnacle.com.au is the owner tenant
acquired-nz.co.nz is added as a member
Cross-tenant sync provisions NZ users as external members in the AU tenant
Users in both tenants can search each other, see presence, and chat seamlessly
Shared channels work without additional B2B direct connect configuration (MTO handles it)

From the users’ perspective, it feels like one company. Behind the scenes, each tenant retains its own policies and administration.

🎬 Video walkthrough

🎬 Video coming soon

Shared Channels & Cross-Tenant Access — MS-700 Module 10

~11 min

Flashcards

Question

What's the key difference between guest access and shared channels for external users?

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Answer

Guest access: external user gets a guest account in your Entra ID and must switch tenants. Shared channels: external user stays in their home tenant, no guest account — uses B2B direct connect.

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Question

What must both tenants configure for shared channels to work?

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Answer

B2B direct connect in Entra ID cross-tenant access settings. The resource tenant configures INBOUND access, the home tenant configures OUTBOUND access. Both must be configured — it's not unilateral.

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Question

Name three limitations of shared channels.

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Answer

1. No apps, bots, or tabs (limited support), 2. No scheduled channel meetings (ad-hoc only), 3. Max 10 shared channels per team and 50 external teams per shared channel. Also: no @team mentions, private channels can't be shared.

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Knowledge Check

Pinnacle Corp wants to collaborate with Partner-Tokyo on a shared channel. Tara configures inbound B2B direct connect in Pinnacle's Entra ID. Users from Tokyo still can't access the shared channel. What's missing?

Knowledge Check

Pinnacle Corp acquired a NZ company with its own Entra ID tenant. They want users to see each other's presence and search across tenants WITHOUT migrating user accounts. What should Tara configure?

Next up: Teams Phone & Resource Accounts — the big one: PSTN connectivity options (Calling Plans vs Direct Routing vs Operator Connect), licensing, and resource accounts.