How do I setup Nagios to meet the following notification cr

Nagios Nagios Configuration support
1

I have Nagios1 (Internal) and Nagios2 (External) monitoring the same service, ServiceA. Currently, I receive duplicate notifications from Nagios1 and Nagios2 when ServiceA is critical.

How do I setup Nagios to meet the following notification criteria when ServiceA is critical?

  1. When only one Nagios detects ServiceA is critical, do not send notifications.

  2. When both Nagios detects ServiceA is critical, send one notification