Hey Teahouse,
To quote Ashley in a prev post,
"IIDs are not constant - they change as you destroy and create objects, so you can never be certain that an IID refers to a specific instance.
You probably want to use UIDs instead, which permanently refer to a single instance."
But to take a stab from a different angle you could try to set variables for the objects once they pass a point by laying down invis sprites and then using "Object is overlapping Sprite - Set animation frame to X".