If you installed the Audio Files with the game, then go to where the radio station audio files are, and move them somewhere else, make some blank audio files of the same format as the original radio stations, and name them exactely as the old radio station audio files were named. Then when the game comes to play them, they will be blank.
Thats one way, or another is make audio files that have a few of your own tracks in each one, and put them in the radio stations audio file.
Why would you want to get rid of them anyway? They are class, funny as well. Especially KChat and VCPR.