I have been in this situation a few times ....with either 3 long separate rooms....I was in the middle lobby to my right a dinner room & to my left a library converted into a dinner room, or playig a cocktail hr inside and a connected Outside deck for guests also which required multi speakers in & out, ... aside from using the HOUSE PA Ceiling Speaker system to distribute your sound which I don't suggest as damage to their system could be imminent unless it's a good quality audio system most aren't....and difficult to adjust different room volume levels during each song with a house unit & your own. I would use separate speakers in EACH ROOM hooked into your main mixer using separate channels to control each room.