Help with tsome unit triggerings

[Icspark]

okay so i was trying all the units for fun, and decided to go for undead campaign units first. I found this hero called Mal' Ganis, he has two unique abilities , one to convert villagers ( commoner) into zombies and the other one to "preserve" these zombies. i need help creating a trigger that can some what reverse this preserve skill because when u Soul preservation the zombies just disappear and they dont come back.... i want to make skill that can summon back all the zombies I've preserved in the past.

4 xample i use it on 4 zombies, i want to make a skill that can re-summon those 4 zombies...

thx.

 

[redscores]

Well, thats hard, I think, how many different types of units can be converted? The Problem is to detect the original type of the unit.

 

[Icspark]

i'm not sure, the description was convert an villager to a zombie so i just tried it on villagers only on villager 2 not villager 1 not sure if it works for villager 1