Restricting the users using applications.....

Hi All,
I am applying Group Policies in our office in Windows 2003 Domain. All the clients are xp sp2.
Actually i want to restrict the users by using group policies.We have different departments like developers,office administrators, etc... The issue is i want to customize start menu like for office administrators can see only ms-office,adobe reader,messenger in the "all programs" menu. But i installed Firefox, Nero, vlc media player , php and Winzip in all systems. If a developer login to the system then he should see all the applications in "all programs" menu and if a office administrator login to the system then it should show only ms-office,adobe reader and messenger.
I enabled
"User Configuration >> Administrative Templates >> Start menu and task bar >> Remove common program groups from Start menu option"
then all the applications are removed from all programs menu. but i want to restrict some applications only according to the user.

Please anyone give me some idea about this issue...

Thank u...