Don't put it in the map, put it in the coding?
<> Memorise BGM (map?)
<> fade BGM (map?)
<> play BGM (choice for cutscene)
<> ~~cutscence~~
<> fade BGM (choice for cutscene)
<> Play Memorised BGM (back to map)
That should work fine if the vollume works and the music is fine anyways.....