Maybe you can cut your static geometry that way, that all polygons with a certain material are in one layer. In LW or Modo I can select a material of a scene. So I can cut it out and put it in an extra layer. So when you have 10 materials you will have 10 submeshes. But this makes only sense for a certain area, like a room. In an outdoor scene you also have to cut it into parts that way, that the view frustum culling can switch it off, when they are no more visible.