Background Mode - Any control ?

Hi, i have a meditation application and try to keep playing the audio session in background mode.

I just figure it out how to play sounds in background with this thread : https://forum.unity.com/threads/how-do-i-get-the-audio-running-in-background-ios.319602/

However it looks like i have absolutely no control once the app is in background.
User are supposed to listen a ~10 minutes audio file with some ambiance sounds (loop).

When i go in background i can still hear everything correctly but the ambiance sounds will never stop.
I'd like to stop the loop mode of the ambiance sounds once the ~10 minutes session is over. I'd like to send information to server when the session is over too.

Is there a way to still have a bit of control on this?

Thanks.