From what it sounds like, you are wanting a sort of 'surround sound' affect from a 4 watt audio output audio chip. Like what I've heard out of my computer's sound card and multiple speakers? Good luck and forgetabout it. Ain't gonna happen with the components in a typical radio (of any kind, CB/ham/etc.). I would suggest looking for some sort of 'surround sound' amplifier that could be fed by the radio's speaker jack. I'd bet there would certainly be a market for such a thingy, but probably a limited one.
At home you could probably feed the radio into your computer's sound card. Mobile, some AM/FM/stereo radios have sound input jacks.
I think I'd give it a test run before plunking down much money for such a thingy, I have tried it and wasn't exactly thrilled with the results. But then, I don't expect 'surround sound' out of a 'communications' radio to start with, it really doesn't help anything. Oh well...
- 'Doc