BIG-IP : disable further processing for event -- except for diagnostics

Refer also to the syntax possibilities of the when clause.

https://devcentral.f5.com/wiki/iRules.when.ashx

You can define a priority for each event. I recommend this as a best practice, so that if multiple iRules get assigned on the virtual, you know the sequence in which they will fire.

You could use the priority to setup flags and only exit out from your last event processing iRule.

Best.