apply group policy to one subnet at a time within an AD site?

Hi All, I know that you can deploy group policy based on AD sites, but what if the site contains multiple subnets?  We're rolling out an agent that affects networking and although we tested on a small group, we'd like to limit potential damage by only applying the agent to one subnet at a time.  Is there a way to do this using GP within a site with multiple subnets?

Thanks!