private boolean checkMonopoly()
   {
      if (group.size() == 2)
      {
         if (group.get(0).owner == group.get(1).owner) return true;
      }
      else if (group.size() == 3)
      {
         if (group.get(0).owner == group.get(1).owner &&
          group.get(1).owner == group.get(2).owner) return true;
      }
      return false;
   }