Can i use Welcome screen, but box will check domain credentials?

There is an XP box on our domain that we want to run the welcome screen on,
but i would like to be able to remotly administer from my desktop.

i want the XP running in workgroup mode to check credentials on a domain,
even if it isn't on the domain. (The only reason it's not on the domain is
because you can't use the Welcome Screen then)

i tried going to the "Users and Groups" applet, and add to the machine's
Administrators group the domain group "MYDOMAIN\Domain Admins", but it
simply refuses to let me prefix anything with anything other than the
machine name.


i know what i'm doing is not possible, but i want to bitch and someone else
to feel my pain.