If you are semi-far into the game and have a sniper with "in the zone" you could take two heavies to blow cover, and an assault to aid you in the process of removing them from cover. Once out of cover, the Sniper can do his part pretty easily. Here is a text guide on TrueAchievements xbox section
TrueAchievements and here is a video as I am sure my description may not help many.