You can check out this link to see how I handled FAQs
It is really a full blown help center.
I am using conditionality to make the groups visible…I am using a single RG and changing the datasource based on the URL.
Pay attention to the URL when navigating through the help center articles and sections.
Here is a link to the forum TIP I put up about how to create the dynamic breadcrumb navigation
For the repeating group on the category aspect of things, I am not using group by…instead it is a simple search constraint to only show the articles that belong to the chosen category.