since im a kind guy, i'll tell you. . . It aint that difficult, although i havent experimented on it. And although i know it's something like DotA's black hole
Anyways, you HAVE to use move unit instantly. Unless you're using WEU, which has the unit slide function. The trigger for your ablity to basically should go like:
Trigger 1
Event:
A unit casts an ability
Condition:
Abiltiy equals to <whatever it's called>
Action:
-Create special effect at <target point of ability being cast>
-Trigger turn on <trigger 2>
-wait (Depends on how long you want your spell to be>
-Trigger turn off <trigger 2>
Trigger 2
Event:
Every 0.01 seconds
Condition:
none
Action
i'm not sure if this works. It works for single units though)
-move units within <your own radius> rage of <target point of ability being cast> by offset 2 towards (i'm not sure about the angle)
This is about all the help i can give. Sorry if it doesnt prove useful enough. Just pray some skilled trigger artiste comes to your aid