Adding posts as a third level in category drop down

Hello Everyone,

I’m working with a theme at the moment that has the pages displayed at the top, and then a second bar for post categories. I have 6 categories with around 3-5 child categories in each. Hovering over the parent reveals the child. I’m looking for a way to hover over the child to reveal the posts within that category. My first thought was to add the names of the posts as categories and then use some form of redirect plugin. Is this the best way?

Another option would have been to replace it with a custom menu as another thing I need is clicking on a parent category to go to a page showing only its subcategories rather than the posts.

Thanks, Nathan