Here's the situation: In iTunes on the iMac, I've configured the AppleTV as a second set of speakers. It works fine -- I can pick a song and it will play in the office and living room simultaneously.
Now, if I then pick a song in the living room on the TV, it will start playing the new song there, but the first song will continue to play on the iMac, thus losing synch. If nothing is playing on the iMac, and I pick a song on the TV, it only plays on the the TV.
Is it possible to get these two fully working together in both directions?