Collider Key in TriggerEvents question

My question is basically if and how you can use the Collider Key to access data about the collider in question.

In my game I want different trigger colliders on the same entity by using a compound collider. These different trigger colliders have some different effects, and I'm thinking of using the "Belongs To" filter as sort of a tag to make sure that the trigger gives the correct effect. To do that I need to get data about the trigger collider whenever a trigger collision is detected, and I assume that Collider Key is the way to do that. Does anyone know how you actually use them?

 

Can someone who figured this out please reply back with the details ^^