Bluetooth/MP3/Pandora???

[Gas Man]

Ok I bought a new Garmin Road Tech Zumo 660. It has a, yet to be determined, "nice" phone bluetooth setup. It's nice if it works well. I'm unsure about the microphone setup.

It bluetooths with my phone fine, I can make & receive phone calls from the garmin, even see my phones phonebook, and call logs.

It has a MP3 player that works well.

HOWEVER, it won't receive streamed audio data from the phone (ie: pandora) to the garmin.

The motorcycle kit provided with my HD version has an audio out stereo plug that I can plug into my stereo input plug on my radio of the bike.

I want to be able to listen to pandora on my phone and still be able to hear the garmin navigation... all via the same singular stereo input on my bike.

The garmin will bluetooth to a audio headset.
I do have a 3:1 stereo adapter I can run. But that is simply MORE cords!

Is there a bluetooth "junction box" that will have a stereo audio out???? Receive the headset audio from the garmin and bluetooth audio data from the phone (pandora)????

Trying to get this new crap setup and tested before my run south to the BRP & Rally.