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TaranjeetSM11's avatar
TaranjeetSM11
Copper Contributor
Dec 04, 2023

Add a shared-mailbox in one Entra ID Tenant to a M365 group in second Entra ID Tenant

Hi

 

Is it technically possible to add a shared-mailbox in one Entra ID Tenant (source) to a M365 group in second Entra ID Tenant (target)? If not, what are my options if we need to be able to allow the users in second Entra ID tenant (target) to send messages to M365 group in their tenant and it gets forwarded / delivered to the shared mailbox in the target Entra ID Tenant (source) where the shared mailbox is hosted?

 

Thanks

Taranjeet Singh

 

exchange
microsoft 365

2 Replies

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  • VasilMichev's avatar
    VasilMichev
    MVP
    Dec 04, 2023
    Add the shared mailbox as a Guest user in the other tenant, which in turn will allow you to add it to the M365 Group (subscribers list). Or directly configure forwarding via Mail flow rule.
  • LeonPavesic's avatar
    LeonPavesic
    Silver Contributor
    Dec 04, 2023

    Hi TaranjeetSM11,

    unfortunately, it is not possible to directly add a shared mailbox from one Microsoft 365 tenant to a Microsoft 365 group in another tenant.
    Shared mailboxes can only be accessed by users in the same Microsoft 365 tenant.

    But, there are a few workarounds you might consider:
    1. Microsoft 365 Inter-Tenant Collaboration:
    Microsoft 365 provides several options for inter-tenant collaboration, which include using a central location for files and conversations, sharing calendars, using IM, audio/video calls for communication, and securing access to resources and applications.
    Microsoft 365 inter-tenant collaboration - Microsoft 365 Enterprise | Microsoft Learn

    2. Distribution Group:
    You could create a distribution group to send mail to another address, but you can't reply from the domain of the original tenant.

    3. Single Tenant with Multiple Domains:
    Another option could be to use only one tenant with two domains, using some users with domain1 and others with domain2, and you can use shared mailboxes with different domains or not and you can set access between all users using any domain, but all of this with only one tenant.

    Shared mailbox access from another O365 tenant - Microsoft Community Hub
    Accessing another Shared Mailbox in different Office 365 tenancy? - Microsoft Q&A
    About shared mailboxes - Microsoft 365 admin | Microsoft Learn

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    Kindest regards,


    Leon Pavesic
    (LinkedIn)

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