audio broadcasting script

i hope this is the correct place to show this.

i want to run a internet music service
when any new clicks to listen the show instead of the script starting from the begining, i want the script to carry playing.
lets say i have 10 mp3 and currently 15 users are listening to track 7 when user 16 joins i want him /her to recieve track 7 instead of starting from track 1.

here is a short metal idea
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1.) Have an M3U file point to the stream script.
2.) The stream script would string together the MP3 files, figure out where it should begin the stream based on the time of the request, and push that to the audio player.
3.) The underlying playlist (including location) could be kept in a database, text file, or in the stream script itself.

can someone point me in the right direction
i need the script with no bangs and whistles, just the core is ok.

please help
TL