I have 2 different ideas of how "multi-room" music should be handled. Neither of which are ground breaking. One is the party mode i posted a screenshot of above. The other is a "send to" menu.

I used to do send to menus only. You pick up a remote select a source and it turns on in the room you are in. If you want to "send" music "to" other areas you press the send to tab and there i had ON/OFF/VOL for every room in the house. I would also make presets like "ALL" or "MOST" or "PARTY" that would turn multiple rooms on. All is every room, most or party would be specific rooms. Those preset buttons would be right next to the volume controls for all rooms. They were just a quick way to fire up a bunch of rooms at once. After you set volume you would tab right back to control the source.

Then we started using better programmers and the Party Mode menu replaced Send To. It's so much easier to use especially with the volume level presets. Once you get 3-5 presets for different levels/scenarios there really isn't any need to individually adjust volume IMO...just like with lighting. But you might as well have the ability for the once in a year moment when someone wants to do it.

Now i am trying to use both Party Mode for parties and Send To for Suites. Our clients will have a guest bedroom + closet + Bath + Balcony. Or a master bed with a balcony, sitting room, his closet, her closet, bath, shower. I think the Send To menu is perfect for this situation. You are hanging out in one of the suites getting ready for dinner or whatever and you want to play music or listen to a sporting event everywhere. You fire up the source then send it to the other areas.

Party Mode is typically accessed from the "Features" (junk drawer for misc sub systems and custom menus like power control or sprinklers) menu. Send To is accessed via button or tab within the selected AV sources menu.