You group users by assigning them roles at the same organization: organizations as user groups.
For example, to create a user group that has translator role permissions to a translation memory:
You can create any number of such organizations, for holding links to resources and granting to groups of users the appropriate roles for those resources.
To provide another group of users different permissions on that resource, create another organization, Reviewers-EN-FR, say; assign users the reviewer role at Reviewers-EN-FR; and then add a link from the TM at Reviewers-EN-FR.
It is possible, but not advisable, to allow a number of people to log in with the same user name.
Topic: Published: 27-Jun-2012