Restrict your campaign objectives so that kills will count ONLY if they are against specific types
CRIMINALS / PIRATES: Kills will only count against those whose security status is -5.0 or lower. Good for anti-piracy campaigns.
INDUSTRIALS: Kills will only count against industrials and freighters such as Fenrir, Mammoth, Occator, Prowler, etc. Good for campaigns attacking trade lanes.
MINING VESSELS: Kills will only count against mining vessels such as Hulk, Mackinaw, ect. Good for campaigns attacking miners or mining operations.
STRUCTURES: Kills will only count against strucutres such as Astrahus, Keepstar etc. Good for attackign enemy assets.