Setting User ID for group of PCs

How can I set and Aministrator’s User ID for a group of computers on a network using Win2000 Server.
We have 20 computers in a lab that are part of a domain “env”. I want to set a User Id in the Server that works only for these 20 PCs but not the rest. What is the best way of doing this, in such a way that allows the password of the User ID to be changed regularly?

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