Tripecac

I'm trying to find a way to get rid of the hardcoded subdirectories in this:

albums/aaa/index.html : songs/aaa/*.xml
albums/bbb/index.html : songs/bbb/*.xml
albums/ccc/index.html : songs/ccc/*.xml
etc.

Is there a way to do this?

I tried:

albums/*/index.html : songs/${subst albums/,,$$(@D)}/*.xml

However, the subst function evaluates to blank. It seems like the $$(@D) cannot be used within a function in the prerequisites list.

Any ideas?

Thanks!

Travis