OK, the GOOD news is that you CAN purchase multiple different parts from Kawasaki, and wind up with a very good WIRED intercom system that will permit both the rider and passenger to talk to each other, and to listen to the most-excellent Kawasaki built-in radio. You can even buy MORE cables, and gain the ability to plug in additional sources, like your iPhone, or an "aux".
The BAD news is that even if you do all of that, and do not hang yourself on all of the wires, you will still NOT be able to talk to any other bikes unless you add the CB.
I have researched all the fun out of this, and decided to go with the Sena SMH10 bluetooth system. While I lose the ability to feed radio directly from the built-in Kawasaki unit, I CAN access music from my iPhone, can talk to my passenger, and can talk to other bikes using compatible bluetooth setups.
I am still trying to find a way to rig-up an audio out from the Kawasaki radio, and then feed it into a bluetooth "dongle", so that I could listen to that in my b/t intercom.
It is VERY disappointing that Kawasaki did NOT make its oem system bluetooth compatible.