Menu with locked sections

Hi!

I am trying to build a menu in a Lectora SCORM course and could use some advice. The menu should consist of four tabs, one for each chapter, and when clicking one of the tabs it shows a list of all sections in that chapter. Now, all of this is pretty basic as I can just either make a bunch of buttons or use the menu tool, but here comes the difficult part: I need the sections that the user has not visited to be greyed out so they are unclickable. What would be the best way to approach this problem? I guess it's a two part question:

1) How do you keep track of which sections the user has visited (keeping in mind that this is a SCORM course)?

2) How do you compare the visited sections with the displayed sections?

Hope someone has some good ideas.

Thanks in advance!

/Mikael