private void unbatchSubGraph(Spatial s) {
        if (s instanceof Node) {
            for (Spatial sp : ((Node) s).getChildren()) {
                unbatchSubGraph(sp);
            }
        } else if (s instanceof Geometry) {
            Geometry g = (Geometry) s;
            if (g.isGrouped()) {
                g.unassociateFromGroupNode();
            }
        }
    }
recursively visit the subgraph and unbatch geometries

@param s
jme3-core/src/main/java/com/jme3/scene/BatchNode.java