This is basically the way you do it, though you will have to disable culling (frustumCulled to false on the mesh) then since instanced geometries aren’t culled anymore. To save memory you could place null-objects in blender as placeholder and give them a name for when you traverse through the scene on the import.
If you’re interested, im very soon releasing a IndexedScene with auto-instancing that also keeps culling, you find some information here. It helps to render very large and rich scenes you couldn’t render with a regular scene.