Bluetooth Audio Mixer For ATV

So I am trying to round up all the pieces to build a bluetooth audio mixer for my RZR. So I would like it to do is take 2 audio sources (3.5 mm from phone for music, and input from CB radio) and stream that to my headphones in my helmet. I believe the RN-52 would be would I need to do this but I need some guidance on mixing the 2 audio sources together before sending into this board.

Ideally I would like the music to default to playing, but when output is detected from the CB to switch to that audio signal instead, then switch back to the music after they stop talking. I also plan to run a button to mount off this board so that I can engage the CB and speak back through my helmet into the CB.

I have not bought the RN-52 yet and I have not bought the CB yet so if you have better alternatives please suggest them.

Any advice on how to go about accomplishing this with the audio signal switching? I feel confident I can make any required code for this work once I get the required pieces and circuitry setup.

There does not seem to be any place for an Arduino in your project.