Looking for a group file management system

I'm looking for a content or file management system / plugin that would allow an admin to upload files to a WP site and allow users to access files via read-only. Allow custom tags, lump files in specific groups and configure user access permissions for groups. Also a history of who's read a posting and/or accessed a file would work for environments that need audit and compliance logging. Oh, one last item.. Posting of file allows the options of notifying that user group.