Yes it's a great addition. Would be nice, if GS would document such things in new features in GDL as well. No good feeling to solve things with complicated constructions, if there might sleep a smart, but undiscovered solution. How often have I missed this feature. I tried this in earlier years with older ACs. Don't know, what made my try it again.
Thanks for checking out. I will keep this information alive. It's exactly, what I was looking for. I have added an algorithm for the room_number, which analyzes the existing number and offers a list of numbers in its neighbourhood. Renumbering is so much easier than the slow changing to the interactive shedule.