The question isn’t very clear to me but i’ll attempt to answer anyway, forgive me if it’s obvious to you:
What you describe is the behavior of “custom post types” When you create custom post types you define a slug like your “suburl” and “suburl2” and all posts created under that type fall under site.com/suburl/post-title
I’m sure that if you first create the necessary post types and then change the type of each post to fall under the proper type you can achieve that structure.