change severity levels of availability monitoring

As you may know:
OpManager has four different severity levels for the alarms. Severity levels of device down alarms (availability monitoring) are already predefined

Here is the list with the severity and the events which will trigger the alarms with these severity

1)Service Down: When is service down and URL monitor is down

2)Attention: When the device is down for the 1st poll in availability

3)Trouble: When the device is down for 3 consecutive polls in Availability

4)Critical: When the device is down for 5 consecutive polls in Availability. This is the highest severity in OpManager.

5)Clear: At any stage if an alarm is cleared.

The question is : How to change these default settings?
Is it possible: Critical: When the device is down for "1" consecutive polls in availability