We're currently going through an acquisition where the new company will operate with a certain level of independence. However, we want to ensure that both Microsoft tenants can work together smoothly, allowing some of their users access to our Teams and SharePoint resources. I'm fairly experienced with single-tenant management and can write PowerShell, but I'm feeling a bit lost on where to start with this cross-tenant collaboration since there seem to be various approaches. Any advice, documentation, or personal experiences would really help!
5 Answers
We have cross-tenant collaboration set up for a specific app at my workplace. I wasn't heavily involved in the setup, but it seemed fairly easy. From an admin perspective, it was really simple; we use SSO for authentication. Different groups get assigned their respective access levels. It's pretty neat that I can switch to their tenant in Teams. Just remember, working with an external company requires a bit of trust, but since it's a partner or subsidiary, that's usually less of a concern.
Multi-tenant setups can be pretty straightforward! There are some limitations, especially with syncing users who have legacy authentication enabled (you should ideally disable that). To get started, you'll want to enable the organization in the host tenant, invite the other tenant, and have them accept your invite. Once that's done, follow the guide for auto-syncing users between the two tenants. Just a heads up—every tenant involved in the Multi-Tenant Organization needs at least one E5 or Business Premium license.
Honestly, if it were me, I’d just suggest migrating their tenant into yours. It can save a lot of time and hassle.
We're exploring the Multi-tenant Organization functionality too, but haven't started testing yet. The main issue seems to be around group syncing since they don't sync across tenants. From what our CSP mentioned, modern collaboration features, Global Address List (GAL), and free/busy information work well, but there are some challenges to watch out for.
I heard that group-sync is in development! You might want to keep an eye on the Microsoft 365 roadmap for updates: https://www.microsoft.com/sv-se/microsoft-365/roadmap?id=518221
This is fantastic news! Thanks for sharing the link!