[N85]

Create a new group (i.e. XP Power Users) and add the users to this group.

Right click on the OU containing the computers. Select the Group Policy tab. Select Open.

If you're using GP Mgmt Console a new window will pop up, locate your GPO, right click edit.
Go to Computer Configuration\Windows Settings\Security Settings\Restricted Groups\

Right click restricted Groups and select ADD GROUP. Type in the newly created group (i.e XP Power Users)
On the next window go to the THIS GROUP IS A MEMBER OF field and click add, type Power Users and click OK. (do not browse for power users).

Apply Ok
Refresh Group Policy and if your setting are correct if you check the local POWER USERS group on aq machine the *XP POWER USERS* group should be included, thereby giving all users of that group local Power user access..