Slitherine

I have created a music mod http://slitherine.com/forum/viewtopic.php?f=147&t=44031. I was wondering if there is a way to have mp3s rotate. My 1st attempt was to label each mp3 individually and give them the -1 theater identifier. But the game would not rotate the songs it just play the same song over and over. My solution was to create a 30 song mega mp3 but some want the songs to shuffle basically. Can anyone offer a possible solution I can't think of here?

I'm afraid that the only solution is to create a 30 song mega mp3.