In Kanboard, each user can be a member of one or many groups. A group is like a team or an organization.
Only administrators can create new groups and assign users.
Groups can be managed from User management > View All Groups. From there, you can create groups and assign users.
Each project manager can authorize the access to a set of groups from the project permissions page.
The external id is mainly used for external group providers. Kanboard provides a LDAP group provider to sync automatically groups from LDAP servers.