Linked roles and posts

Great plugin!
Very useful for my needs. Was thinking if it would be possible to:
A) link user roles so that roleA can see media files from roleA, roleB.
roleB can see media from roleB and roleC. and so on obtaining linked roles that can see specfici other roles files.
B) Link files to a specific post so that when editing post with ID 5, users can upload files which will be visible only when editing that specific post still respecting the role capabilities.
I ask this because I am creating a platform where each post will be a project and various user profiles will have to upload their own set of files and I would like these files to be tied to that project only and not selectable in other projects.

Thanks in advance