Where best to bundle incoming effects in a gameplay event

I am making a block and parry system for my melee action game. I have a vision of being able to use a gameplay event to indicate that a melee attack has connected and that effects are going to be applied, then have responders to that event override the effects until all responses have resolved.

Currently I can’t decide the best place to put the array of incoming effects. Should I use the GameplayEffectContext within the event? Or the target data? Or somewhere else?