Slider process interaction with layers

Hello! I'm also having Slider problems. I attached my project with a description of the problem, but here it is again:

I’d like the learner to be able to use the slider (on the base layer) to choose a scene – an office (sub layer 1) or a waiting room (sub layer 2). Based on the scene they’re on, I’d like to deliver content. Easy enough, right?

My problem is I’d like to use the same slider on the base layer for the sublayers so the learner doesn’t get stuck on a sub-layer; I’d like them to go to the office layer if they’re on the waiting room, and vice versa.

How do I refer to the base layer's slider (SLDR Scene Change) on the sub-layers without having ALL the stuff from the base layer (which has the initial slider on it) on the sub-layers? Currently, the sub-layers have their own sliders – SLDR office and SLDR Waiting Room. Ideally, I’d like them all to refer to and use SLDR Scene Change.

Also, the slider’s thumb doesn’t seem to move from layer to layer. I’d like the slider to reflect the step it’s on – 1 for the office or 3 for the waiting room.

Thanks for any help!