We have a new premium service called Seesaw Plus. Among other great new features, Seesaw Plus teachers can have up to 5 teachers on each class! Here's more information about Seesaw Plus. You can upgrade to Seesaw Plus anytime in your Account Settings.
If you’d like to add more than 5 teachers to each of your classes, please consider our Seesaw for Schools service. Using Seesaw for Schools, teachers can have up to 20 teachers on each class. http://web.seesaw.me/seesaw-for-schools/