@Override
	public void addMetroRoomnumber(String roomID)
	{
		if(metroRoomIDSet==null)
			metroRoomIDSet=(RoomnumberSet)getProperRoomnumbers().copyOf();
		if((roomID!=null)&&(roomID.length()>0)&&(!metroRoomIDSet.contains(roomID)))
		{
			metroRoomIDSet.add(roomID);
			if(!CMath.bset(flags(),Area.FLAG_INSTANCE_CHILD))
				for(final Iterator<Area> a=getParentsReverseIterator();a.hasNext();)
					a.next().addMetroRoomnumber(roomID);
		}
	}