I recently made a SimCity 2000 toolkit for LabVIEW (video link, source code) which plays music, and simultaneously plays sound effects as required. The source code is LV2019, but I can back save it for you if needed. Look in the Sound.lvlib library at Effects Player.vi and Music Player.vi for an idea on the state machines. The Main.vi calls both of these VIs, and issues messages to play music and sound as needed.