If the rooms are really separate, do you really always want the same music playing in both rooms?
Guess I'm not seeing the full layout of the space in my mind.
If there's a +chance+ you'd want the two rooms to be able to play different tracks simultaneously, I think I'd go with 2 jukes, and maybe just point one to the other's library of tracks to keep track duplication down.
If you really want to always play the same tracks, I'd think you'd be good with a mirrored screen and any old touchscreens that look like mice to windows.
The reasons are:
1. Mirroring the screen will deliver the same image to both monitors. Easy as pie.
2. you +would+ have effectively 2 mice going, but, as far as I can tell, any device that looks like a mouse to windows, controls the single mouse pointer unless the app is specially coded (ie mame). In this case, you actually WANT both screens to control the mouse in the same way.
Yes, you MIGHT get into issues where 2 people are trying to play different tracks at the same time, but they're right around the corner from one another and it'll be obvious that someone else is moving the cursor around onscreen.
Or, you could put up a heavy duty header and take out the wall anyway. That's what I did (er had done, it was a little too risky for me to take on by myself) on a kitchen remodel I did.