Hi,
You can use Group Policy Preferences to achieve your goal.
1. Create a group policy
2. Under computer configuration, select "preferences" and "control panel Settings". Right-Click on "Local users and groups" and select "New Group".
3. From "New Group" wizard, select "administrators" and add members.
4. From "Common" pane, check "Item-Level Targeting" and click "Targeting"
5. From "Targeting" Wizard, click "New Item" and "Computer Name". Enter a computer name on which you want to apply the previous setting and click OK. As the result, the account MYLAB\rlaine will be added to Administrators
group of computer L000001.
6. Apply the group policy to the computer and check result
Note : the Group policy can contains multiple instances of local administrators group (for example one item by computers in your environmenment). Each item will be applied to the correct computer depending on "targeting" rules.
For information about group policy preferences :
here
Reg