Adding a group to OU as local administrators to PCs

Hi

I am looking for the Group Policy or another solution to add a group to the Local Admin group on a set of PCs. I have been looking for the group policy, but have been unable to find it.

For example, the group it is regarding is the Design group. I need to be able to have the designers able to log in to all the design PCs, but do not want this to be a full domain setting.

Thanks. Also, could you please tell me where exactly this policy is.