А ничего,что Power Users являются по своей сути Администраторами ,так что с таким же эффектом можно включить в группу администраторы.

1. Start Active Directory Users and Computers from any domain controller.
2. Create an organizational unit, and then move all of the appropriate workstations and member servers to that organizational unit.
3. Create a global group in that organizational unit, and then add the appropriate users to that group.
4. Start Active Directory Users and Computers, right-click the organizational unit, and then click Properties.
5. Click the Group Policy tab, click NEW, and then name the policy.
6. Click the policy, and then click Edit.
7. Right-click Restricted Groups (under Computer Configuration\Windows Settings\Security Settings\Restricted Groups), and then click Add Group.
8. Click Browse. Focused on the local computer, click the group to which you want your global group to be a member (in this case, the "Administrators" group), click ADD, and then click OK. You are returned to the group policy and you see the administrators group listed in the Restricted Groups window.
9. Right-click the group, and then click Security.
10. To the right side of the Members of this Group box, click ADD, and then click Browse.
11. Locate the group in the organizational unit that you want to place in the administrators group, and then add it the group. After you do so, close the group policy.
12. At a command prompt, type secedit /refreshpolicy machine_policy /enforce, and then press ENTER.