Your new snakes should probably go in the rack and the rack be kept on the other side of your reptile room or in a closet. Or the new ones kept in separate cages, again well away from the rack with your current two. Also you should not handle your old snakes after handling new ones without first sanitizing your hands. These are basic practices to keep all of your animals safe. There is a recent thread about someone bringing home one or two new snakes and putting them into an existing rack with others. Several days later they had 5 dead snakes. A harsh lesson about quarantining you don't want to learn first hand