Structure targeting ability

[Mechanical Man]

Is there any ability in warcraft that targets buildings by default? It must be an active ability, so I can detect it. I'm asking that because I want AI to target it (don't come with lame trigger here, dun wanna triggers), using abilities like firebolt don't work, I tried it, it targets only units.

 

[Amigurumi]

Ability firebolt:
Targets Allowed - Air, ground, organic, enemy, neutral
change this to
Targets Allowed - Air, ground, organic, enemy, neutral

then it should be able to cast on buildings.

 

[Mechanical Man]

I know, but computer controlled players don't know that.