code: public void drawGroup(Object parent, Object object, Matrix transformation) {
  		createOrUpdateGroup(parent, object, transformation, null);
  	}
docs: Creates a group element in the technology (SVG/VML/...) of this context. A group is meant to group other elements
  together, possibly applying a transformation upon them.
  
  @param parent
  parent group object
  @param object
  group object
  @param transformation
  On each group, it is possible to apply a matrix transformation (currently translation only). This is
  the real strength of a group element.