Hello David.
Review Ticket State feature. http://sambapos.com/wiki/doku.php?id=states
As ticket state changes you can enable / disable or show / hide ticket’s command buttons. So you can configure SambaPOS to enable / disable close and settle buttons as a specific ticket state changes. (eg CanSettle). Finally you can setup actions & rules to update ticket state to (CanSettle=False) when kitchen order added and (CanSettle=True) when a table selected.