With Garmin audio panels you just plug your music source (I have used FM radio, CD player and MP3 jukebox successfully) into Music In and then you can route it to all headsets, isolate the pilot or isolate the crew (ie two pilots.)
If a radio transmission comes in music is supressed in any headset that isn't isolated from the radio.
It works brilliantly and I am listening to the Today Program or 6 o'clock news most flights.