As I said the BA330 will still run in stereo with a line out to the other amp. The stereo effect is minimal but with the speakers in the same cabinet and so close together I think thats all you cand get. If it were me if your other accepts stereo ins just use the BA330's line outs to it and let them both run treble and bass. If no stereo in just run a mono line.
Another option would be to get a small powered sub to run with the BA330. Or two small powered speakers like the Podiums 8's and put those on stands farther apart. Nice stereo split that way.

Good luck