Update external-identities-overview.md

Author: csmulligan

articles/active-directory/external-identities/external-identities-overview.md

@@ -28,6 +28,8 @@ The following capabilities make up External Identities:
 - **B2B direct connect** - Establish a mutual, two-way trust with another Azure AD organization for seamless collaboration. B2B direct connect currently supports Teams shared channels, enabling external users to access your resources from within their home instances of Teams. B2B direct connect users aren't represented in your directory, but they're visible from within the Teams shared channel and can be monitored in Teams admin center reports.
 
 - **Azure AD B2C** - Publish modern SaaS apps or custom-developed apps (excluding Microsoft apps) to consumers and customers, while using Azure AD B2C for identity and access management.
+-
+- **Multi-tenant organizations** - Collaborate seamlessly with users in other tenants that belong to the same organization, using cross-tenant synchronization. 
 
 Depending on how you want to interact with external organizations and the types of resources you need to share, you can use a combination of these capabilities.