I'm writing a php file upload script for a project - I have seen all the great opensource ones out there, but I've decided to do my own as I have a level of user access rights that I can't seem to find anywhere. 

So this is what I'm trying to do:

1. Normal file uploads area, exactly like [elFinder](http://elrte.org/elfinder/demo)
2. Some way to restrict certain users to view the folders and/or files, depending on what group they belong to. I need to do this as this is for an organisation I work in where certain users can only see the docs they are supposed to

Originally I decided to make a mysql solution where each and every folder has an ID, and when you create a folder you specify the groups that are allowed to view that folder - but this doesn't seem like the most elegant solution. 

Can anyone suggest a theoretical way to do this? I'm happy to code it all in PHP, but I just can't get my head around the best way to do this.

Is there some way (short of naming folders in specific ways), that folders and files have properties I can exploit here?