Groups can be added on the main Groups page.
Groups can be set to different levels of privacy depending on your needs. You can also categorize groups (Production, Company, or Social), and create Groups as subgroups.
For example, you could create a Private Production Group for The Wizard of Oz, and invite your whole crew to join the group. Then you (or anyone who is an Organizer) can create subgroups for different departments or teams so that everyone has a collaboration space.