You can't render one object multiple times per frame, but you can create clones of an Object3D and make them use the same mesh. To do this, do
Object3D obj2=new Object3D(obj1, true);
obj2.shareCompiledData(obj1);
obj2.shareTextureData(obj1);
The last two lines can be left out, but that will reduce performance and increase memory usage. As long as the clones are 100% clones of the first object, you should use them.