That trigger requires you to select a premade unit, so that specific unit would be manipulated for your trigger.
I would make a trigger to help you with your problem, but I dont have that kind of time tonight.
There should be a boolean? condition or maybe even some sort of action that involves only that type of unit. So instead of using a premade, such as Medivh 0274, you can find the correct trigger that manipulates any Medivh unit.
I tried... I hope this could help. =(
~Saryeit