Hi,
Thank you very much for your kind words!
Okay, I think your first step would be to categorize the posts/pages. For each franchise, I would make a category (ex. Planet of the Apes) and put all the Planet of the Apes pages there. This way, there is now a connection between each page. I think this is the easiest and most reliable solution, as it might also get handy in the future with other plugins as well.
Then, there is a feature in the plugin, that allows you to include results from specific categories only: Documentation – Restrict to category
For each page, you could create a search bar, and configure these restrictions individually. I believe this is the easiest and most straightforward solution.
If you are planning to have lots of categories, then instead of creating a search bar for each, using a minor custom snippet could be more convenient, so that only one search bar is sufficient. In that case, this knowledge base with the custom code can be life saving. It will automatically restrict the results for the current page category.