Assign a Menu to a Category

I have searched many sites and posts and they all talk about assigning a category to a menu; I would like the opposite. My settings/theme allows posts to have their own menu. I already have posts and many posts will be added automatically in the future. What I would like is to have posts that are in a certain category to be assigned a certain menu.
Also would be nice if the category itself had that same menu. the way it is now any category shows the default menus. there has to be a way to assign a menu to a category and all its posts. Is that possible? if not how do I make the post bulk editor show the menus available so I can assign a menu to posts in bulk?

Thanks