Hello,
i wondered, if gp is planning to enable the audio player to change variations (with markers etc.). So every musician playing with playback is able to program the changes. You wouldn’t have to change sounds(key or guitar) or Pdf pages with a additional controller. This would be a killer application.
Hello @don , welcome here 
Have you already done a search on this subject on the forum?
Maybe this topic will be useful to you:
Automatic variation changes from audio file time?
Hello Hermon, did the research, but obviously not good enough.
Didn´t dive in GPScript. I will try to manage the scripting.
Thanx for the quick answer.