As a project group administrator, you know that the key to any user's access to the
project group and the projects belonging to the group, is in the role you assign to the
user. You can do almost all the role-related activities with project groups that you could
do with individual projects.
You can create site-wide roles and assign the users to those roles and then bring
them into your project group. You can create roles specifically for your project group
and assign users to those or use global project roles, as required. The permissions
inherited
through
the assigned roles are subject to the "Prevent Inheritance" option setting done while
creating the roles.