Maybe they don't link, but I certainly got aggro'd by 3 of them at the same time and barely escaped with my life (RDM23/WHM11).
I was down here looking for the tomb, doing the 'Grave Concerns' quest, ran right past it and into this area where all th emobs are considerably harder.
Still, the Nachzehrer's conned EP to me, so I thought "HA HA! Easy" {Hmmm...} think I made a mistake. lol