Well you could just create a virtual directory for them, they are on the same server right? Just not in the web folder?
Just toss in a little line to your httpd.conf file in your Apache config directory.
ScriptAlias /files/ "/filelocation/"
Naturaly you'd replace the filelocation with the directory where the files are located, basicly what this does is puts that directory and everything inside of it on the site without actualy having the files physicly in the webroot.
So the user would end up accessing those files like so:
http://webserver.com/files/filename.mp3
of if it was inside a direcotry in that directory, like so:
http://webserver.com/files/directoryname/filename.mp3
This works as long as the files are located somewhere on the serve machine and (I'm not sure about this one) posibly on a shared local network.