Look into how to create new audio buses for the game and route all sfx to a sfx bus and all music to a music bus, that way you can mute or alter the volume separately. Like some people might want a low volume on the music but keep the sfx high. Though how difficult this is for the engine you are using I don't know. I haven't experimented with volume sliders or such yet but in Dragonslide I made two separate channels to mute music and sfx because I got a comment wishing for the option.