From what you desire and what you are considering sounds like more work/Cost and concern in the long run. Why not look into a wireless system like sonos or squeezebox set up. The will allow you to play what ever you like in either location and have full control of volume and,selection in each room with a remote. the only extra cost after the wireless system is a boombox/mini system to play through in the kitchen (thinking that the main system is in the livingroom). Squeezebox has an boombox wireless system for such applications that do not have full systems to connect to. I am thinking of picking one up for the garage and use on the rear patio during cook outs.