Actually, since the Passport 8500 has a mode where it can identify the frequency of the signal, it wouldn't be far from that to be able to filter frequencies. The cost and the processing time may be prohibitive for the consumer market, however.

Brad "Diva": 2004 Mazda 6s 5-door, Volcanic Red Rex: 1988 Mazda RX-7 Vert, Harbor Blue.