Hi Janine,
No that was not obvious :) I was just clarifying the way you are accessing the field value.
In the where clause of the repeater you can use this condition to filter the documents. This is assuming that value of department is already on the page.
postDept = '{%postDept%}'
Kentico will replace value inside {%postDept%} with the value of a department for that page and filter results for you.
Let me know if it works for you
Cheers,
Chetan