That's easily said then done. Sometimes I swear they deliberately aim for me especially near the end of a mission. Nothing is more frustrating then almost beating a mission only to have a beam kill you without any warning.
Yes, hostile AAA beams do deliberately aim for you at the end of the mission. In fact, they always aim for you.
If you've ever done 'A Game of TAG' then you will know what I mean. Sometimes the ULTRA-anti-fighter beams on the Warspite skewer you along with the Shivan fighters when you TAG 'em from behind...1 hit KO in a Ulysses...

Although I've been skewered by friendly AAAf beams several times when I try to gun down hostile fighters (ungrateful bastards...).
That said, give the Colossus all ULTRA anti-fighter beams, set the pilot and gunner AI to General and crank the difficulty to insane...and stay in a safe spot while watching Shivan wings get impaled from 4 km away

(any fighters with 100 hp or less get instagibbed, like Dragons and Basilisks).