The only immediately obvious idea I can think of is a variable for every single page. That would indeed be cumbersome. To make things a little bit easier, you could do a set of device variables and a set of page number variables. Take your device with the most number of pages and make that many page variables, then a variable for each of your devices and just store the current device and the current page number. That will still be a beast to program because you are going to have to write a set of processing macros that will return you to the correct page.

I have the same issue on help pages. I just make a help screen for each device and the return functionality takes them to the root of the device. Let us know if you come up with anything.

Regards,
-aedile-