Add build phase for 7-8 player

The 5-6 player extension for Catan has a "special build phase" where all players can build at the end of anyone's turn (only using cards in hand, no trades to other players or to the bank). This typically leads to a more balanced game because players have a means for keeping their card count low when there are many turns that pass before it comes back to them and it keeps the game interesting even when it isn't your turn, which is more important with a larger group.

If you could add this as an option during game setup for the 7-8 player extension, it would be much appreciated.