Disable use of Outlook Express

I am managing a Windows 2000 domain, with W2KPRO clients.
I am using Active directory & Group Policy.
I have the need to disable the use of Outlook Express (actually, all email clients) to all users except those that are members in a AD group.
Any suggestions?
Can this be done using the “Don’t run specified Windows Applications” in Group Policy (Administrative Templates/System)? If so how?
Thanks in advance!