Restrict by computers names

Hi,

I want to deny access to a particular folder on Win 2k server which is the PDC in the network, to a set of computers.

All our users login to their local systems as Administrators and all know the domain password to access other files and folders in the server.
I want to deny access even if the users enter the password from a set of computers, only for few folders.

Can anybody tell how to do this.

Thanking you,
Parameshwar