how do I add a global security group to the local administrators group?

I need to add a global security group to the local administrators group on all my PCs (about 80) and am not sure how to do that.
I know about the “net localgroup administrators \ /add” but that only works for the PC i’m on. I tried adding this to my script, but it doesn’t work because the users don’t have admin rights.
Is there a GUI program that will do this?
dana@amazingfacts.org
Thanks,
Dan