Jeff,
That's totally possible with a bit of page and 'jump' organisation - but you should be careful as it's quite easy for even highly intelligent (!) learners to get lost in the web of complex lessons. I'll show you the format of pages I think you need to do this (if I understand your request properly) but it's also worth considering whether this one lesson should be actually split in two or even three (depending how many content pages you have in each section), to make the navigation simpler; that is, split the lesson at the end of cluster 1 and also possibly at the end of question two.
Is this what you are aiming for?
Have one first screen on which the jump buttons say "section one', section two' and 'section three'. Alternatively have this like a menu page and use hyperlinks to get to each cluster.
In between content and question pages within your cluster one and cluster two have normal continue/next progression jump buttons.
At the end screen for both cluster one and two your continue/next button should go back to the first screen - they should have a label explaining this and not just 'next' etc. Something like, 'end of cluster, return to main menu screen'
Cluster three continues in the same way except the last jump is to the essay page, and this jumps to end of lesson.
A warning: be careful with this as if your students don't visit every page they may not get a full completion on the lesson.
I would actually have the first screen explain the navigation for the lesson. Then after each cluster do NOT go back to a main screen as this could mean your students miss pages. Just make it clear on the end of cluster page what happens next. This way they visit each page only once and navigation is simple.
Actually, to be honest, I wouldn't make a lesson that was so complex. I went down this route when I first started lessons and quickly abandoned it. Students respond much better to separate lessons labelled as 'part one', 'part two' and 'part three' much better than a complex lesson with contents pages. it also means you're unlikely to have them miss out screens as they go through.