With VCE, you could do a relay that chooses a random value and setMusic based on that. The problem with that would be it randomly cutting out in the middle of the loop, although that could be avoided if you give it a different, carefully timed delay for ending each loop.
I think I'm going to try and do a video on this, actually.
Sorry, there's no way I'm going to work out my hackiest events since BlockoMYST while Skyrim is three clicks away. Hopefully a real script could do this much more efficiently.