HI Abdulilah Saleh
If I'm understanding correctly, You can do this with just a trigger and a script using the "musicoverride=x" action.
"This replaces the current background sound/music with a new file
and plays the new file continuously"
Check your scripts, you may have something already that "overrides"
the background music. If not use something like this..
:state=0,plrwithinzone=1:state=1,musicoverride=$0
:state=1,plrwithinzone=0:state=2
best
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