Ok. It was a general question. I have some BF-F8's tuned to GMRS channels and Marine Channel's. Some car CB's . As for who ? Maybe car to car and to hand held.
Have not taken my Technician but have done the studying.
The intercom is for multiple people inside the car to talk to each other, driver to spotter or navigator or whatever. Everyone has headsets.
From where to where is the crux of the question. Wouldn't be difficult to add audio out from a radio as an external in source into his intercom (so everyone could hear traffic coming over the radio) but beyond that the two systems don't really cross over.