[hobbit] Purple Status

I thought I had seen somewhere in the MAN pages about the ability to set hosts so that if it is not responding to ping then all of the other monitored services should not also send an alert because they are dependent on the ping working.

If one of my machines goes offline because someone turns it off I don't want the other services to also send me e-mails of their failure or purple status. How do I set alerting that if the connection is lost the other services won't alert also.

Any ideas?

Thanks, Jason