Custom Ability - Snare Trap

I have an ability that I am having trouble making, called Snare Trap. What it is supposed to do is create a trap (that can be destroyed) and when a hero comes in range, a dummy unit is created that immediately ensnares the hero. Currently I have a trap set to a variable (the trap is independently created by a trigger) which then adds an event to another trigger: "A unit comes within 250 range of SnareTrap."(SnareTrap is the variable) The problem I'm having is that if the trap dies, it is recreated and reset to the variable, but that doesn't effect the event I added earlier. Is there a way to clear the event and readd it with the newly specified variable, or just a better way to do this altogether?

Give the Snare trap an attack that deals 0 damage, give it 'Ward' status(or if you don't want it selectable at all, add the 'Locust' ability to it) and create a trigger that checks when a unit is attacked by your trap and then create your dummy unit(or use your trap) to cast ensnare on the attacked unit.

Thanks sc, I didn't even consider using an attack. Always so many ways to do things and I always try the hardest ways first for some reason.