Networks

you need to groups in active directory.

group 1 = "project" folder full access
this will contain all of the people who need full access

group 2 = "project" folder Limited access
this contains everyone who get the limited access.

create the groups, assign the users to the groups and assign the groups folder share permissions based of the repective access levels.

your dept. head and his sect. are getting lumped in with the full access. Network Admins don't have all day to %^&*&%% managing groups so i wouldn't create a 3rd group for them.

Let me confirm what you want.
You have 3 folders and you want different permissions on each folder.

You can right-click on the folder and select 'Properties'. Choose the 'Security' tab and click 'Add'. You should be able to select a group called 'Users' or 'All Users' or 'Everyone', etc, then choose the specific permissions with the tick boxes below.
You can choose different permissions for each 'child' folder as long as there are no inheritable permissions on the 'parent'.

EDIT: <b>Make sure you have administrator privileges.</b>