Perfect explanation matx, far better than i did this time of night. I knew exactly how to do it in front of my GPO at work but could not get it into words.
Stations ---> Computer Config ---> Security Settings ---> File system
Right click in the right pane and 'add file'
Note - certain locations are set like %programFiles% %Systemroot% %SystemDrive% etc
For example I have: %ProgramFiles%\Groupcall & %SystemDrive%\Darkedit
You can then add users with the relevant NTFS settings and file propagate etc.