Cross-Tenant Shared Meeting Room Spaces

To allow users from two M365 tenants to share meeting room resources like booking rooms and accessing calendars, the key step is setting up proper calendar and mailbox sharing in Exchange Online. You’ll need to configure cross-tenant calendar sharing and delegate permissions so users can book rooms across both environments. Beyond that, for Teams meeting room resource sharing, no extra Teams-specific setup is usually needed if Exchange sharing is in place. However, syncing meeting room objects in the Global Address List (GAL) across tenants isn’t automatic—you’d need to set up directory synchronization or use a third-party solution if you want the rooms visible in both tenants’ GAL. Hope that helps!