Auto log off user after a program is closed

[See full original topic here, still unsolved as of April 20, 2009:
http://www.edugeek.net/forums/windows/33732-auto-log-off-user-after-program-closed.html ]

Alright so here's the deal. I'm building 8 machines. Windows XP Professional. Games like Starcraft, Warcraft, Age Of Empires etc. will be installed, so the machines are 1.8GHz, 256MB of ram, and a 10GB HD. Yes, it's what I had lying around lol. So I'm building these as console systems, they aren't connected to a domain, and once configured they will be frozen with Deepfreeze. They're using the Windows Welcome screen for logging in, each game has it's own useraccount within a very stripped down interface. So for example, click STARCRAFT user with a Starcraft icon as the user icon, and Starcraft launches since it will be in STARCRAFT's Startup folder. Sounds simple so far! I'd like to take it a step further. When the game is quit, no matter what game it is, can I have a script [I need your help ] that will log off the user and send them back to the Welcome screen? I don't need to prevent minimizing or anything like that, these aren't super secure machines. I'd just like the process to be as smooth as possible. So here's what'll happen.

?User powers up machine
?Welcome screen appears
?User selects game [user account]
?[User account logs in] Game starts
?User closes game or chooses quit [user account logs off and sends user back to welcome screen]

That last bracket is what I need help with. Any ideas? Thanks so much in advance!