Irule Question

This VIP is a "dependent" for another GTM wide IP (another service). Since this VIP is not falling down, the GTM wide IP is still available and the service hosted on that wide ip still available.

Consider VIP_A pool have 4 servers. My requirement is if three servers in the pool of VIP_A goes down, VIP_A needs to go down. Another GTM wide IP configured with VIP_A as dependency pool (Its dependency pool, not direct GTM pool). So if VIP_A not available, GTM will failover to another site where all servers available.

I know this is crazy solution but this is the only way to failover two services if most of VIP_A pool members are down, I have found a way to do this using a script. Thanks for your help