Well, I don't think that there is any application that can do that, but yes, you can avail the music using while you are at the call, i know a little trick and i have discovered it accidentally, i know i was on the what's app and at the same time i was on the call too. I have accidentally pressed the play button of the music file and viola, what i am hearing was I was listening music while I was on the call.

Well, If you found out any application that can do the same like during a call i can play music and let other friend also hear the same

, that would be great.