Yes. First, you must add background music for the project under Tiger > Site > Background music. You will probably also want to increase the initial volume from its default setting of 25%, which can often make it seem that there is no music at all.

Now, mouse-hover on the thumbnail for a folder and choose More... Edit. On the right, expand the Image data panel. There, you can add music tracks for that folder.

You're welcome.

I knew it was buried in there somewhere, but it's certainly not immediately obvious. Had to do a little hunting.