If all the study rooms are booked when you need to study with your group, you can always use the tables found on all three floors of the library on a first-come, first-served basis, no reservation needed. Anyone can use an unoccupied study room until the person that the space is booked under arrives with proof of the reservation (confirmation email)
For additional information, contact the Library Building Coordinator at librarybc@csueastbay.edu