Outlook: Set up room search

Create room resource and set capacity, address (Street, City, State/Province, ZIP/Postal code)

New-Mailbox -Name "Besprechung-GL-HQ" -DisplayName "Besprechungszimmer Geschäftsleitung Berlin" -Room Set-Place -Identity "Besprechung-GL-HQ" -Capacity 10 -State "Berlin" -City "Berlin" -Floor 12 -Floorlabel "Stockwerk 12"
Create room list(s). MS recommends several room lists per location, which represent different levels (building, floor). The building list contains all rooms at the location, then for each floor another list with the rooms of this floor.
New-DistributionGroup -Organization firma.onmicrosoft.com -Name "Hauptgebäude Berlin" -RoomList -ManagedBy userXYZ@firma.onmicrosoft.com Add-DistributionGroupMember -Identity "Hauptgebäude Berlin" -Member "Besprechung-GL-HQ" New-DistributionGroup -Organization firma.onmicrosoft.com -Name "Hauptgebäude Berlin - Stockwerk 12" -RoomList -ManagedBy userXYZ@firma.onmicrosoft.com Add-DistributionGroupMember -Identity "Hauptgebäude Berlin - Stockwerk 12" -Member "Besprechung-GL-HQ"
Wait and see (in the tests there was no visible result until the following day)
Create a meeting in Outlook, open the scheduling wizard and start the room search. The cities should appear there and the room lists that contain objects of this city.