This website will allow you to log in and view the meal schedule then you can choose a day that works for you. Once you schedule yourself you can write a note about what you are bringing so everybody can see the menu and be a part of the planning. If you are not familiar with the "Paleo" diet, there are a couple links to "Paleo" diet websites with recipes that you can choose from.
To log in, once you are on the website enter their last name and the password (their dogs name). Once this is done you can view the schedule and sign up to bring them a meal.