Groups are a collection of Users within Boston, and for which Permissions can be set on Projects that include those Groups.

For instance, when editing the "Nolana Health Care" Group for the fictitious Nolana Health Aliance company, a Group of Users with access to Boston can be created.
The image below, shows a list of Users allocated to the Group and as apposed to the list of available Users who have access to Boston.

NB Groups are allocated to Projects via the Edit Project form, and play no other role other than to be able to have Group based Permissions for Users within that Project.