Perhaps try something like this:
First, create a global variable called "playmusic" and set it's default value to 1. Then put this code in the first layout(this is all in one event):
+Start of Layout
+Is global variable 'playmusic' equal to 1
-XAudio2- Play music "asdf.mp3"
-XAudio2- Loop music
-Set global variable 'playmusic' to 0
The global variable acts like a flag to determine if the music can play or not. Hope that helps.