Dynamically updating page numbers (but not on the page they refer to!)

Is there a way to create page markers which dynamically update, but which aren't on the page they refer to?

So page 1 has a marker saying 'page 20'. If i moved page 20 so it becomes page 40 then the marker on page 1 updates itself.

I'm creating something like a 'choose your own adventure' book with a complex structure where you choose to move to different pages to change the direction of the plot. It would make it much simpler if I didn't have to redo the page numbers everytime I change the page order in the book!