How To Overcome Dwarf Multicannons

I've always been stressed out by rangers who use dwarf cannons but I've discovered a way to overcome it and kill you target. Whenever a dwarf multicannon attacks a certain target, the owner of the cannon will be attack but if the owner is not in a multicombat zone , he can only attack 1 target at a time BUT the cannon will still continue to attack multiple targets. What you do is you keep clicking the left mouse on your target until eventually you attack your target. That's all. The owner of the cannon cannot attack all of his targets made by his cannon so take advantage of this. Remember, please try not to use cannons. Be considerate.