Jarrad_McMullenThanks for your reply.
Indeed the new TAGS do help with room capabilities like certain AV-equipment and such.
Coming back to room-lists: It really seems to be, that The_Exchange_Team designed them to be bound to a location.
Why? If you open the new room finder in outlook there is a drop down named BUILDINGS, klick on it and you see "recently used buildings" (at least this how it's called in my German outlook when litarally translating) and voila, you can choose a ROOM LIST!
Conclusion: Unless this is a translation error, Room-Lists are indeed considered to be a subset of buildings!
So multiple room-lists within ONE building but not the other way around.
Not a huge deal, but this certainly limits some creative use of room lists.