I'm not seeing that behavior in SS6 Update 1 (08.11.09.866 ). A single Named Group is created in each elevation Drawing Model.
If you do not wish to see the elevation labels they can be turned off in Floor Manager, set Floor Parameters > Annotate to False for each floor.
If you do not wish to see the elevation labels they can be turned off in Floor Manager, set Floor Parameters > Annotate to False for each floor.