How do i allow certain users to modify a shared desktop and other users not to be able to modify it?

Stopping Certain Users from Changeing settings on a shared Desktop and allowing other to do so.

where i work certain departments share the same desktop, for example the finance department has a desktop called finance which has 500 users and the marketing department has a desktop called marketing which has 80 users.
i do not want some users in the accounts department to be able to make changes to their desktop but i want some to be able to, team leaders for example.
so i create a new group called accounts desktop owners and another accounts desktop users, i make the users who i dont want to be able to change the desktop settings into the accounts desktop users group and set the file permisions for the desktop folder so they can read but nor write, then i add the users i want to be able to change the desktop into the accounts desktop owners group and set the file permisions on the desktop so they can read and write.

so for example:
users in accounts:

John:team leader
lucy:employee
Jo: Secratery
Jocy: Accounts Manager

so i would want John and Jocy to be able to change the desktop, to add a new folder or link to a file, but i do not want Lucy and Jo to be able to Modfy the desktop.

so the groups are

John: accounts Desktop owners
Lucy: accounts desktop users
Jo: accounts Desktop users
Jocy: accounts desktop owners

this tip can also be used on shared folders for setting who can do what in them, its reely just useing the NT File Permisions to its limit! i think there a brilliant feture.