Sort category list parents before children

We run a cinema and use category “Film” as parent to categories “Barntill?ten”, “Till?ten fr?n 11 ?r” and more. (Age restrictions)
The categories shown by #_EVENTCATEGORIES for eachfilm title is sorted by first letter, i e the results are
“Film Till?ten fr?n 11 ?r”
“Barntill?ten Film”
We would prefere the last one to be
“Film Barntill?ten”.
I can fint no way to sort so that parents are listed first and children after them.
Any idéas would be appreciated!