When a room mailbox is created in the cloud, its recipientTypeDetails property is set to RoomMailbox. In a hybrid environment, on-premises room mailboxes are synced to the cloud through directory synchronization. After directory synchronization occurs, the recipientTypeDetails property of on-premises room mailboxes is set to MailUser.
New-DistributionGroup –Name <NameOfRoomList> –roomlist
Add-DistributionGroupMember <NameOfRoomList> –member <OnPremisesRoomMailbox>
Article ID: 2904381 - Last Review: 28 Dec 2016 - Revision: 1