Hi Frank,
Let me start by saying that I am not going to explain what a domain is to
you. There are ample resources on the idea of a client server directory
service system vrs a peer to peer network. Its a foundation principle in any
MS network with over 10 nodes. I would reccommend going out and getting a
book on basic networking principles.
I am not trying to be harsh, but somethings have to be considered foundation
knowledge.
Now to Group Policy.
Group policy, no matter what its name infers, has nothing to do with user
groups. Under special circumstances in can, BUT if you are using it that way
you are using it incorrectly.
Group policies are groups of diffrent settings that cover evreything from
the system environment, to automatic software installation, to security
setings, to well, its a massive load of functions. These Policies are then
applied to parts of your directory service; Sites, Domains, or OUs.
To achive the desired effect you would make one policy that hides the Screen
Saver tab and attatch to an OU. Then move the user accounts that need to be
effected to that OU. Youmay need to make an OU.
If this a single computer then it may be more advisable to use a socila
engineering rather than a computer engineering approach.