Make navmesh agent ignore mesh of certain area type

Hi : )

so basically what I want is for one type of enemy to be able to walk on water and one to fall right through the water and walk on the ocean floor.

So I made a navmesh area called water and set the water plane to that. And made underwater area and set the plane underwater to that. Then I took the navmesh agents and did so the first couldn't navigate on water area and the second couldn't navigate on underwater area.

This however doesn't work, the Jesus agent walks on the water just fine and gets to his destination, the underwater agent however cant jump down through the water (I have placed off mesh links). So he can't get to his destination, he just stands cowardly by the waterfront.

Is there a way to do this?