Or create a computer group policy on a ou at a higher level
Go in the security of the policy on that ou
Remove the "Read" and "Apply Group Policy" for "Authenticated Users"
Create your own Global Security Group
Add all computers that you want to have this policy applied to this group
Add it to the Security for the policy on the ou
Give it "Read" and "Apply Group Policy" in Security
Now add the modification for the registry to the policy
If you do it via a computer startup script, it is only applied when a computer is switched on