How do I change a collision event?

I have two objects that are interacting in an event. The event triggers when one of the objects collides with the other object. However, I do not want this to happen. I want the event to trigger when the hitbox of one object is completely enveloped in the hitbox of the other object. Thanks in advance!

You might want to pin a small sprite(invisible) to each object at their center. They should be appropriately sized so that they only overlap or have a collision when the one object is completely enveloped by the other and write your condition based the center pinned sprites on overlap or on collision.