I didnt play with group vol ramp but to highlight your grouping issue.. Last yr i spent quite a bit of time with level 2 support. I believe the driver has been updated since.. To group rooms all I did was set each room to the same heos endpoint, which then seem to start a session.. my issue was after turning off the room, a room randomly started playing audio.. heos blamed the customer, saying that someone local or remote was in the app and start playback?? this was a condo that the balcony speaker would randomly start after c4 turn it off.. I fixed this by ramping vol to 0 before turning the room off, so that when/if the room started playback it would not have vol..