Need some help Isolating Layers

Hello friends:

I need some help isolating audio tracks from one layer interfering with another. On a slide, I have 5 layers, on on each layer is an audio track. When a user is on Layer A and before the timeline of the audio on that layer expires, they chose Layer B [like a curious cat], obviously there are two audio tracks now playing.

How can I isolate each of these Layers in such a way that if Layer A does not conclude its timeline, or while Layer A is still playing, no other layer by action can, the only override I want is to advance to the next slide with the slide navigation control, but not another Layer chosen on the same slide?

Oh, I tried to use variables on each layer, i.e. set layervar = 0, and set it to 1 when timeline concludes, but that doessn't help either. Maybe I am not using the variables correctly.

Thank you for your help.