I agree with Toradog and use these switches to switch on running lights etc. I have found this company reliable and helpful. As Toradog says there are probably other systems around. A thought has occurred to me and that is how long and how loud do you want the music to be played at? This might determine what you use as sound playback.
best wishes Tim

Well, there is the OLD school way of using a servo to actuate the start/stop button. I had used that a a small tape player, about 25 years ago. Now a days we have electronic switches which plug into the receiver like a servo. The switch, either a single, double or gang switch, interrupts the current in either the hot or the ground circuit( your choice ). Very simple to use and set up. I have been using switches made by the Component Shop. https://www.componentshop.co.uk/action-electronics/switches.html I find them to be easy to use and reliable, but there are quite a number of manufacturers out here. Just do a search.