Windows 2000 Users

I just received my first batch of Win 2000 machines. They will be running on an NT network, and I can’t figure out how to create users so that they have the same profile whether they’re logged into the local machine or the domain. Even though the account names and passwords are the same under both 2000 and NT, it insists on creating two separate profiles. Can someone tell me how to get them to use a single profile?