Add logged on user to local Administrators group via group policy?

Hi,

I want to add:

[DOMAIN NAME]\Domain Admins

AND

the user logging in to the computer, to the local administrators group. Not [DOMAIN NAME]\Domain Users via computer policy and restricted groups. How do I do this via a group policy? :-|...

Regards,
Allan Kjaer
Microsoft MCP, MCDST, MCSA 2003, MCTS Configure Exchange 2010, MCITP Server Administrator 2008
Check Point CCSA, CCSE
Cisco CCENT, CCNA