Win2k Terminal Services?????????????

Here is the situation:
A company has 4 remote office and some internal users using an Access97/VB6 application through terminal services. It’s pure Terminal Services in Application mode (without Citrix) on only one server. Ocasionaly Access97 database needs to be reindixed/repared during the day.
BUT the stupid users keep connecting to the Terminal Server and tring to log on to the Application.This is really annoing since, I need to disconect them all the time, and when i disconnect one, someone else connects.
So is there a way of “Locking” Terminal services for the maintanence period? I know I can’t stop the service 🙁
Any sugestions?
Thanks,
Victor