The ONLY instance wherein a DPS should need to watch their enmity for the tank's sake in a 4-man is if the DPS outclasses the tank's gear by A LOT. So really only at level 50.

If you are about as geared or even slightly under the DPS and they are taking enmity from you, you either have two outstanding DPS in your group that are purposefully attacking different targets to mess with you, or you are bad.

I will say that OP might be having issues if the NINs have Aeolian Edge and they don't have RoH yet. And the only dungeon that is applicable in would be toto-rak. Potentially something like a PLD in Brayflox or Cutters if you don't have shield oath yet as well.