What if there are 2 people who cannot stay the second night but there are 2 different people who can stay the second night?
As long as the minimum number of guests have reserved the minimum two (2) nights, it does not matter. On night one, Mary, Carol, Jane, Karen, Linda and Debbie stay and on the second night Mary, Carol, Jane, Lori, Jenny and Maggie stay the second night. There are the 4 minimum guests staying the minimum required nights.