While groups allow teachers to organize their own students, shared classes allow teachers to organize students and share those same classes with other teachers. To create a shared class, just click the "Shared Classes" link, create a class, and share those students with another teacher.

Please note that any teacher can edit either the students or the teachers in a shared class. However, once a class has been shared, those students will remain on a teacher's roster, even if they are removed from the shared class.