Create room distribution list
To summarize rooms and workspaces into groups you have to create a distribution group from type -RoomList via Exchange PowerShell. Room lists are specially marked distribution groups that you can use the same way you use distribution groups.
Exchange OnPremise and Exchange Online
Use Exchange PowerShell to create a room list
This example creates a room list for building 32.
New-DistributionGroup -Name "Building 32 Conference Rooms" -OrganizationalUnit "contoso.com/rooms" -RoomList
Use Exchange PowerShell to add a room to a room list
This example adds confroom3223 to the building 32 room list.
Add-DistributionGroupMember -Identity "Building 32 Conference Rooms" -Member confroom3223@contoso.com
Use Exchange PowerShell to convert a distribution group to a room list
You may already have created distribution groups in the past that contain your conference rooms. You don't need to recreate them; we can convert them quickly into a room list.
This example converts the distribution group, building 34 conference rooms, to a room list.
Set-DistributionGroup -Identity "Building 34 Conference Rooms" -RoomList