Add more than one song to a powerpoint slide show

I am trying to find out how to add more than one song to a pp slide show. Thing is that my slide show lasts for probably 10-15 min., and I need to find a way to play songs thru the entire show. I don´t want to loop the same song over and over, and I can´t use the play for x slides function, since I don´t know how long the presentation will take.

One should have the option to add a playlist! Any workarounds?

Thanks!