office365 multi tenants GAL

Question

Dear All,

we have a scenario that is under one Holding Group we have 10 companies (tenants) having office365 subscriptions i.e E3, E1, Exchange Online. now we need to create a single GAL combining all tenants (global address list) it should be common to all tenants.
we don't have an AAD sync. need solution thanks in advance

Answer 1

Hi @shaiksaj

Generally, it is not feasible to share GAL among Office 365 tenants (Some 3rd party apps and services may support this).

However, multiple on-premises AD forests can sync with one Azure AD. In this case, all forests must be reachable by a single Azure AD Connect sync server. You can refer to the article below for more details: Topologies for Azure AD Connect

This thread discussed the similar question: Sharing contact details between tenants

And I also found an article here, but this may not be suitable for your scenario: Microsoft US Sovereign Cloud Myth Busters - A Global Address List (GAL) Can Span Multiple Tenants
(note that: This is to help those organizations that must deploy into both a Commercial tenant and a GCC High tenant at the same time. Many of those organizations have a requirement to light up a consolidated address book across both tenants.)

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Answer 2

@shaiksaj not sure if you are still searching for a solution. But we partnered with Microsoft and build a solution for just this.

https://www.federated.directory

It lets you connect your various AAD tenants and share the GAL between the connected companies. Let me know.