[chirp_devel] receive-only channels?

is there a way to indicate that a channel is receive-only? The FT-4 is tri-band for receive, but (clearly) does not transmit on the FM broadcast frequencies. In UHF and VHF, the receive-only frequency ranges are larger than the allowed TX frequencies of rthe European and US versions. My current code is schizophrenic: my valid_bands list has the full receive-only band for FM broadcast but only the TX-allowed bands for VHF and UHF I would like to permit a user to program the RO frequencies but to know that TX will be disabled on that channel, and for the test suite to work with this.