Sharing meeting rooms between 2 office365 Domains/Accounts

Hi guys!

I am trying to share meeting rooms between two separate office 365 domains/accounts. 

I have tried going through the steps here:

However I am still no able to see the meeting rooms of the other domain.

A couple of questions.

1) For this to work, do the accounts need to be connected to AD and or ADFS?
2) I have been reading about Federated trust. Is this a necessary step? I cant seem to find where to set the federated trust up? I have looked on multiple O365 accounts... maybe the portal view changed.

Any help advice would be welcome.


***Post moved by the moderator to the appropriate forum category.***


Hi Jasmine - I'm going to have to disagree with your statement/answer above as I have just finished allowing an external non domain user to book the calendar.

This can be set up in a few steps.

#1. Via the FOO admin portal: set up an organizational relationship with domain BAR.

#2. Via the BAR admin portal: set up an organizational relationship with domain FOO.

At this point both companies/domains should be able to see each others free/busy times as well as meeting room free/busy time via Outlook.  (NOTE: to see the meeting room in company BAR from company FOO, you will have to enter the meeting room email address IE: *** Email address is removed for privacy ***)

The problem at this point is that if they try to book the meeting room, the room will not process external request.

(so you can see how they might think they booked it and people then double book from FOO .....problems)

So the last step is to run the following via powershell for that meeting room to allow external bookings:

#3 Get-Mailbox "meeting-room-name" | Set-CalendarProcessing -ProcessExternalMeetingMessages $true

references: (connect to office 365 powershell) ( external bookings)

I hope this helps others.


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Question Info

Last updated September 23, 2020 Views 15,302 Applies to: