Suppress alerts based on dependancy

I have Host groups for remote offices. For example I have a Dallas and an Austin host group.

We have VPN\'s at each location. What I would like to be able to do is say if I lose contact with the remote firewall for that group, suppress alerts from all of the other devices in that host group. Maybe some way to designate a single host as the primary for a host group. If the primary is down, suppress alerts from other items in that host group.