This is actually a script feature request.
Like you already have llSetParcelMusicURL which sets a streaming url for the whole parcel, I would like to see the ability to have say something like, llSetPrimMusicURL which is much like the llPlaySound tag where you can hear it's music when within close range. Is it not possible for a prim to do the same thing but instead of playing a wav file it plays from a streaming url?
Thanks.