Animate trouble, finishing an animation loop before going to the next.

Hey, I am currently working on interactive comic book content in Animate CC. I stumble on a problem I cannot solve.

I make a lot of use of looping animation. I use Javascript (because I use HTML5 Canvas) to make those loops with a bit of code where at a certain frame number, the timeline automaticly goes back towards a certain frame number so it loops. The idea is that when the user clicks on a button, the animation goes into the next loop. Now here is my problem, because I want to make this transision as smooth as possible, I cannot seem to make it work so that the animation finish the previous loop before going into the next one. (because I use the fuction: go to certain frame and play() code).

I hope this make sence, I am also not really a code expert, but this is pretty much the only code in my project I need besides the basics.