Dependencies and downstream events

I have spent the better part of a day combing through the wiki and forums posts, as well as the RSM Admin guide. Maybe I am not using the proper terms for what I am trying to do

I am trying to figure out how to manually define device dependancies for a location so that when I lose ping to a device, I do not get events for all of the downstream devices. I am mostly concerned with ping events. For example, if my firewall in the Georgia office is no longer reachable via ping, I only want one event, rather than ever device in that office also generating ping events.

Maybe there already is a way, and I am just not using the proper terms for what Zenoss calls this functionality. If so, please point me in the right direction.

Thanks!