Let me clear my scenario more briefly.
Let us suppose if parent went down .. for example Firewall. In that case what will happen, we will get bunch of emails showing that firewall is down, and other alerts will speak of devices went unreachable. The emails will be as many as the child notes went unreachable.
Can I get a way out of these bunch of emails. Instead of getting alerts separately, can that be classified in single email, mentioning device is down and these child notes become unreachable. Thats all. Dependencies and groups are already built on.