Categorized flyers from subsites

Hi there,
I'm building a system using Pro Sites: Owners of the sub-sites upload their flyers. I need a way to categorize the flyers and the categories will not only be used for the owners to upload flyers from their admin panels but also be used in the main site to show different categorized flyers to the end users. What plugins should I use? Please note that I don't need the Site Category plugin as it's on the sub-sites level, not on the posts(flyers) level.

Thanks
Leo