Same area.. Catacombs, Stairs leading down to second level. Stand on bottom 3/4 steps.
Throw nades at raiders/eitc/officers etc to the left of those stairs (standing looking down the stairs). The rocks alongside of the stairs (that your throwing nades over) will offer protection similar to the fence at kingshead. Its not perfect, if you get too close, they can hit you. I wasnt able to attack the whole floor there, but could get a couple raiders and a merc into each round.
You may not see them mulling about there on the other side of the rocks, but you can keep nading them.
