I believe different music for each map will take some editing of the maps themselves, because maps are exported with a selected playlist already (I believe - don't take my word for it). However, you are able to change the music in the playlist to suit your needs. So specific songs play in plains (not caves) vs caves, you can open up your FeralHeart folder and then open music.cfg. It's rather obvious which is which.
To play any specific song, put your file in FeralHeart > Media > Music (it can be anywhere in the FH folder but the music folder keeps it organized). Since the file is in your music folder, you'd make a new line under wherever you want the music to play and write "media/music/example.mp3" without the quotes, of course.
I think you're mistaken, Kynvuu, unless you have a music mod? o: