[Using PowerPoint 2010, PC]

I'm trying to find a way to use background music on my title slide that will play continuously until my presentation begins (while people enter the room, etc.). That part is easy, but I would like to be able to click for slide advance and have the music fade out (NOT at a predetermined spot in the music) while it switches to the next slide. Is there a "music fade out" transition that I'm missing?

Thanks!