Currently you can only use all "ORs" or all "ANDs" in event conditions for a single event. Or alternatively, use building block events that are referenced by a parent event, which is messy and makes event management complex.

We find that we often create advanced events just to use more than one operator in the event.

Simple example: "brown" and ("dog" or "cat")

Event manager needs to be enhanced to allow more than one operator in basic mode.