Execute Trigger whenever unit is affected by ability

Execute Trigger whenever unit is affected by ability

Yeah, I have a nice trigger function and I want it executed on every unit that is affected by a certain ability.
How would I do that?

Thanks for helping,
Oncer

Event:
Unit casts ability
Cond:
Cast Ability = <your ability>
Act:
<your actions - use 'target unit of ability beeing cast' to refer to the targeted unit>

Sorry, but that didn't help much. I don't want to trigger the event for the unit that is selected by the spell, but for all units that are affected by it.
So, when I have e.g. a frost nova dealing damage to seven units I want to execute the trigger for all seven units.

Any idea?

u can pick all units in range and then trigger them.
But that means you have to do a formula for every spell's range and one if/then/else for each formula

For sure not the easiest way to do it