[SCRIPT] How to make music fade out and new music fade in?

[serbusfish]

I have a set up where when an enemy appears alternative music will start playing (rather than the default enemy music), however when the enemy leaves I want the music to return to the normal level music so I use stopmusic and playmusic commands, but the stopmusic is instant which I would prefer to be a fade, is there any way to do this as the music suddenly stopping is quite jarring?