How did Simon Finch design his house to keep track of his daughters?

Simon Finch was the first person in the family to settle at Finch's Landing.  He built a "two-storied white house with porches circling it upstairs and downstairs" on the property to make his wife happy. This was the same house that Scout and her family spent every Christmas at. Simon Finch and his wife eventually had a large family of eight daughters and one son.  

The eight finch daughters stayed under the watchful eye of their father. Simon Finch designed the interior of his beautiful white house so that he and his wife would know all the "comings and goings" of their eight daughters. On the second level of the house were six bedrooms. Four of these six bedrooms were for the daughters to share. Those four bedrooms could only be accessed "by one staircase." This staircase was called "The Daughters' Staircase," and from the first floor it was only accessible from the bedroom of Simon Finch and his wife. This was how Simon Finch "always knew the hours of his daughters’ nocturnal comings and goings."