Now you can meet gangsters on the streets with tape recorders and playing atmospheric music. And not only that! You can also meet passing gangster cars and music coming from their cars. All this applies to such gangs as Grove Street Families, Ballas, Los Santos Vagos, San Fierro Rifa, Varrio Los Aztecas. You can meet your buddy with a tape recorder on the street, invite him to the team and do anything together to music. If you get in the car together and turn off the radio, you can continue listening to his tape recorder. You can also switch the music of your homies, just press the button while nearby.

The music is divided into 3 groups:
For Grove Street Families - 25 songs;
For Ballas - 25 songs;
For Los Santos Vagos, San Fierro Rifa, Varrio Los Aztecas - 25 songs.

You can decrease or increase the maximum number of songs in the .ini file (Increase only if you have additional .mp3 files, of course).
Also, in the .ini file, you can adjust the volume and the key to switch songs.

Thanks to Vladvo for the test and advice.