Using the iScan software ( included in the scanner ) create a Playlist with only that one frequency in it.
You can " Browse The Library " or Import by Zip Code.
Then write from the SD card to the software.
In the software edit out ( delete ) everything you do not want to hear leaving only what you do want to hear.
Assign it to at least one Playlist in the software.
Lastly write it back to the SD card in the scanner.
Now that playlist has only the one frequency.
I just woke up and still groggy so I hope this makes sense.