You probably could do that without my plugin, but mine would make it easier.
For, you see, when you load a music track with the Soundtrack Manager, you have the option to give it an alias, and from then on, you can refer to the track by its alias. So, let's say you have a switch called "8-bit soundtrack". Every time you load a track, do something like this:
Notice that both "Load" commands are accessing different tracks, but assigning them the same alias. Then, when you play back, tell it to play "Dungeon" and it will play the track you loaded, and until you cleared or re-loaded the track (which you never technically have to do) it would always call the correct one.
You would need to reload every single loaded track when you switch between the two soundtracks, mind you.