iRule to update vip address that DNS entry is resolving to.

In this case it will not be going to the GTM. The Global Load Balancer will just be monitoring the health/performance of the various clusters and updating the FQDN addresses on a separate DNS accordingly. It's been proposed to us that it's possible when monitoring the health (IE, up/down status) but we are trying to determine if that same setup would be possible if monitoring performance with the the Global Load Balancer.