Domain Brain Teaser

At the login screen on an NT 4.0 network there are 2 different domains that can be chosen. When the administrators log onto the machines to fix something, their domain becomes the default domain. So when the normal user goes to log on they have tochange the option to their domain. (I know it doesnt sound like it is that hard, but some users dont even notice and then cannot get logged onto the network). Is there a way in NT to jest keep the same domain at the login no matter who logs in?