Can ITA page (email) me if another computer is down?

I have ITA set up to discover all our servers and some of our key desktop computers.  I have successfully setup Event Filters and Actions which email me via SMTP when certain systems have critical problems, and email me at another address for almost all problems detected.

BUT:  What I'm trying to set up is a notification when certain systems are not found on the network.  Currently ITA displays a "down" indicator next to each system that is not found on the network, but how can I get ITA to email me when certain systems are no longer found on the network?  Currently I only see events that are reported by the Server Administrator or OMCI on the remote system, but I am looking for an event for when  the remote system is not found.