Zoom region - reverse direction

Hi I have a diagram which animates (fades etc) onto a slide in stages.

Each stage is built on a separate layer so once the user has viewed the specific part of the diagram, they click a continue button to move to the next stage (resume slide trigger).

On the base layer I have Zoom regions that zoom in on each stage as it animates in, then pans to the next zoom region when the user clicks continue.

I used the following video as a guide https://www.youtube.com/watch?v=u8opsZ71tBk 

I was wondering if there is a way for the Zoom regions to move in the reverse direction so that if I can have a "Back" button next to the continue button which will pan back to the previous zoom region.

This would essentially play just the base layer timeline in reverse - I'm not sure if this is possible? Any advice would be much appreciated.