Requiring users to view all slides, but also freely navigate

Hello everyone!

I'm having a bit of an issue here, and I'm hoping someone has an idea.  I just recently started using Articulate back in October, so I'm still getting used to some of this functionality.  I don't think this is a simple matter, but hopefully someone's got something!

Here's the deal:

I am creating a module that essentially has three parts.  The users will initially go through the first ten slides or so in a linear fashion.  After that, they are brought to an interactive table of contents I created by hyperlinking a whole bunch of different objects on the slides to other slides.  The purpose is so they can learn about the topics they want to learn about instead of us forcing them through the remainder of those topics in the same linear fashion that the first part was set up in.  There are forward and back "buttons" (basically just shapes I've hyperlinked), and on each slide, there are three topics the learner can choose from (there are ten topics in total).  Finally, the third part is basically just an outro video that thanks them for participating in the course.

This is where my dilemma comes in.  I want to be able to make sure they've touched upon each of the topics (and subsequently all the "sub" slides that come with each topic) before they reach the outro page.

Is there any way to do that?  I've toyed with locking slides, and manipulating the navigation, but neither have produced exactly the result I'm looking for. 

Does anyone have any ideas?  Anything would be greatly appreciated.  Thanks for your time!

~AJ