Creep Aquisition

I'm making a melee map just for the heck of it but I can't figure out how blizzard sets the range at which the creeps aquire your units. They have way too far of an aquisition range. I tried messing with the gameplay constants for creeps but I seem to be doing something wrong. Besides that, when I edit the game play constants, it says that it's no longer a melee map. I know blizzard sets the creep aquisition to a shorter distance for their creeps. How do they do it, and better yet, how do they do it while still keeping the map as a melee map?

Do I have to edit every creep individually?

*EDIT* Sorry, I answered my own question. You just double click on the creep and you can set them to the "camp" aquisition range which is 200 rather than the default range which is 500.*/EDIT*

Or; if I am not mistaken, you can edit the aquisition range in he object editor. It gives you more varied possibilies.