Restrict Use of Some Departments-Accounting Only Departmens

Good morning!  I'm relatively new to maintaining departments as well as maintaining the Department Security Tree, so this may be an elementary question.  We have a handful of departments that only Finance uses for accounting purposes; they are not to be used on positions/job records.  These departments are in our Department ID Tree but not in our Dept Security Tree. We don't want these departments to show up as an option to pick on our positions and job records-is there a way to restrict use of these departments so that no one can access them when creating HR-related records? If