How object affect navmesh generation only for some agents

Hello unreal community,

I am making a game that has different characters (navigation agents) and depending on the type - one type can only walk and others can “hover” over terrain.

Here’s the scenario - a terrain that has rivers. For characters that can walk will descend into rivers, depending on the depth of the river. But hovering units should not descend but only hover.

River is a static mesh plane and the landscape has a sculpted indentation ( depth). But hovering units should not descend but to hover based on the river static mesh plane.

Im having hard time coming up with the way to generate different navigation meshes:
 - one that considered static mesh plane for characters that will hover over water
 - one that will not consider static mesh plane  for regular characters that will descend into water

Screenshots:
https://drive.google.com/file/d/1FbnboGwku4c4WU7UW8NG9c9c67LZTlVt/view?usp=sharing
https://drive.google.com/file/d/1PY1UUSZIhVC8nEThPY4vghWccLr67a71/view?usp=sharing

PS: I would appreciate any help, maybe there’s a different approach but I have not found alternatives. I know about NavArea and NavFilter classes but I can’t see how I can use that here for nav mesh generation.