Q: (from Matt)
I have an Office 365 client who has kind of an unusual setup. First, he purchased O365 directly under a non-profit status. Second, he has an on-premise Exchange 2007 server that hosts several (5) separate email domains. We have configured those domains in such a way that they all have their own global address list, etc. In other words, they are a completely separate as they can be on one Exchange server. He wishes to maintain that same level of separation in Exchange Online. Third, he has already moved some of these domains into his Office 365 tenant.
Based on my research, it looks like the way to do this is either separate Office 365 tenants or something called multi-tenant. I can’t find any information on multi-tenant.
Separate Office 365 tenants would be the easiest solution.
However, I did a Bing search on “Office 365 separate address lists” and came back with the following entry from three years ago:
It appears with PowerShell you can enable the Address Book management role and create address book policies based on recipient filters – not quite what you were looking for, but it gave me hope.
So I then tried “Office 365 separate global address lists” and came back with GAL Segmentation. The best blog post in my opinion was non-Microsoft:
But it certainly sounds like what you were looking for.
I then tried “Office 365 GAL Segmentation” (I love it when the Bing search suggests the phrase I’m looking for as I type it… I gives me confidence I’m going in the right direction!) Lots of Microsoft results including one from TechNet: