if ( previousGroupKey == currentGroupKey ) return true;  if ( previousGroupKey == null || currentGroupKey == null ) return false;  return isSameGroup( currentGroupKey, previousGroupKey );
return isInSameGroup( currentGroupKey, previousGroupKey );
	boolean isInSameGroup( Object currentGroupKey, Object previousGroupKey )			throws DataException	{		if ( previousGroupKey == currentGroupKey )			return true;		if ( previousGroupKey == null || currentGroupKey == null )			return false;		return isSameGroup( currentGroupKey, previousGroupKey );	}