Hi Tobias

In answer to your other questions - the fields institution and department come from the standard profile fields in Moodle. You can store any values you like in here but originally they were designed to store information about an educational organisation - institution could mean school name - eg School of Business and Department could be Economics.

As well as a position hierarchy there is an organisation hierarchy that can be used to store organisation information rather than position information.

The selection  of course members can be done through defining of dynamic audiences based on field values  see http://help.totaralms.com/audiences.htm if you are using Totara 1.1 then cohorts are used in a similar way http://help.totaralms.com/totara_v1.1_help/Cohorts.htm

regards

Craig