moving an active with a radius towards...

Hello,
I am currently working on a little topdown 2 Player strategy game, and I can't get the actual units behave like I want.

I am using a spritebased radius object that gets created when the unit does. through IDs they are parented ontop of the units.

Now, what I want to do is let the unit move close to the target and start attacking when any enemy unit is entering the radius. but I just can't seem to get it down. I tried various mindboggling broken coding attempts... I've been using click projects for years, but if it gets to such complex stuff, I just can't seem to get it right.

Oh yea, the units are using a bouncing ball movement.

thanks in advance!

Referencing particular instances of an object is sometimes complex in MMF2 - search the forums for fastloops, spread values, and possibly also the Select Object extension.