GPO configuration

Hi,
I am confused on the issue of Domains and security boundries. Can I have
different password policies in the same domain? Couldn't I have one policy
that has a 6 character password requirement and link it to a GPO for the
general user, and then have a 12 character password requirement for admin
group linked through a GPO? Also what happens when you have a GPO like this
with password requirements linked to a site that crosses domains? Does it
just not process or execute properly?
Thanks - Wayner
.