Hero attacks hero - creeps respond bug

Ok my map is an AOS style map and I'm having a minor bug. Whenever a hero attacks an enemy hero, and they are surrounded by enemy non-hero units, all these units stop whatever they were doing (attacking other non-hero units for example) and move to attack that hero.

It would be ideal if the units kept on attacking what they were attacking, and not stopping to attack a hero just because they attacked their allied hero.

How does one go about preventing this?

Unfortunately Warcraft has quite a lot of unit AI behaviours that cannot be easily switched off.
In your case it might help to capture all orders given to the units so you can lookup their current target. You could then catch the attack order of the hero and then for all orders immediately after that one reissue the order they had before that.

Granted that would work - I was looking for something a little less complicated than that though - its not necessarily a huge problem - just kind of annoying. I was wondering if it had anything to do with priorities or unit levels (like what determines what a unit attacks first given an attack move-to command). Some unit value that could be tweaked in the object editor.

I had plenty of these things, I found that making every single unit have 0 in the priority field, helps

Thanks I will try that.