I thought that channels 1-7 were FRS-only, 8-14 were shared between FRS and GMRS, and 15-22 were GMRS-only. So channel 9 is available on all of these radios. Is there even such a thing as a single-channel unit? And is there such a thing as a GMRS radio that doesn't cover all the FRS channels?

I'm not too worried about the interference issue since in remote areas there's not much traffic anyway.