I'm wondering if I might be misunderstanding your description, as they are in conflict with what is available on the dashboard and the permissions for it.
In SDL Trados GroupShare 2017, the permission called "View Dashboard" controls if a user can access the dashboard or not.
And e.g. the default "External Translator" role isn't granted this permission.
Further, if a user is granted the "View Dashboard" permission, s/he will only see the tasks, projects/deliveries and statistics for which they have access to (through the relevant organization(s)).
Is this what you were looking for?