I think you need to use nested nodes to define the hierarchy.
An other solution would be to use AddMesh to collapse multiple surfaces in one mesh, then use the SaveB3D source from the archives. The source also explains how to identify certain loaded surfaces by their textures without to use LoadAnimMesh.
An other solution would be to use AddMesh to collapse multiple surfaces in one mesh, then use the SaveB3D source from the archives. The source also explains how to identify certain loaded surfaces by their textures without to use LoadAnimMesh.