If you happen to have Rhino and Grasshopper handy, maybe process the meshes there and use the Disjoin Mesh tool to separate the mesh into separate objects first.Then you can handle more workable meshes in Revit rather than as one massive mesh object.
Whilst I do use mesh/sat in Dynamo from time to time, I find preprocessing can be helpful first to ease the load on Revit/Dynamo after.