Bookmarking for Multiple Users on Same Computer

I am developing training for CD to be launched using shared computers that do not have access to our LMS, but the training is so long that we would like to incorporate some kind of bookmarking feature. Our caveat is that there is a common "log in" for the computers (for example: every just logs in as "Guest").

I have created a log in with an action that adds to and stores each user's ID and is retained between sessions. I have an exit button on each page that places that user's log in ID in a variable on the page that is being exited and I've added actions that subtract the user's ID from every other page variable in the course. So, when the user returns, there is an action on each page that checks whether the ID is contained in the page variable. If it is not contained in the variable, Lectora proceeds to the next page and so on until it finds the user ID and stops on that page. This works PERFECT if the course is a simple "page turn" course. But if you're using a Table of Contents or MENU and have multiple users, and the users skip around, it doesn't work.

It seems that there should be another variable that should store the user ID along with the associated page to return to. So, if you have two users, both IDs and both page names are stored in this variable. Is there a way to extract the appropriate page for each user so that the correct page is displayed?

And there may be a better way to accomplish what we're trying to do. Anybody have any ideas? Thanks in advance for your help!

Tabitha