Thank you for the help! :) I got it worked out.
For my situation, I called on the instance count of the object and told it to -1 in order to refer to the actual ID #.
So, if I have five instances (IID #s 0, 1, 2, 3, 4) and want to destroy the last created/existing instance, then -1 gets me to that correct # and destroy it. So far, it's working.
The instructions I gave go like this:
->PlayerBox | On collision with Enemy
-->(sub-event) System | Pick Sprite instance (Sprite.PickedCount-1) => Sprite DestroyRhindon2013-01-27 09:26:30
I'm seeking Narnia. Who wants to come with me! Aslan is on the move!