Windows XP Automatic Log-off in SBS 2003 Domain

I manage a SBS 2003 Doamin with 50+ Windows XP machines. I have Screen Saver
to automaticlly turn on after 10 minutes the require a pasword. The problem
is that there are a few machines that are shared and when the user leaves and
forgets to log-off the screensaver activates and only the logged-in user or
myself(Administrator) can unlock the screensaver to allow someone else to
login and the use the machine. Is there away to allow any user to log-off
the user and login or have the machine automatclly log-off after logon hours
expire?
.

Loading