How can I make my hero a non-priority target?

[Marine]

There is a tower, and twenty AI Peasants are running by it. My unit, a Hero, is also running by it. The tower engages the Peasants only if they come first. The moment the tower realizes my hero is there, it switches it attacks from the nearest peasant to me. How can I stop this from happening? I want the peasants to be just as likely to be hit as the Hero.

Changing the priority of the unit: No effect
Changing the formation rank of the unit: No effect
Changing the point value of the unit: No effect

There is one limitation to how this must work; my unit MUST be a Hero. If changing the Hero to an ordinary unit is the fix, then that won't work for me.

Thank you for reading, and please help.

 

[Spartipilo]

I think the tower attacks the nearest damage source. Try checking the attack range of your hero/peasants.

Also, I think towers attack the higher damage source.

Also, I think you can change your peons category, so they are seen as "units" and not "workers", since common WC3 workers are lame and not smart targets for towers in melee games.

 

[MajorKaza]

Order of picking targets:

1: Hero (only if focus on heroes is checked in AI)
2: Unit with lowest defence (armor, not hit points)
3: Nearest unit

If you didn't set AI then it has focus on heroes checked by defoult.