Same in norway. One ballot per party. In local elections we vote for both council and municipality, so there's two sets of ballots. Council ballot goes in one box and municipality ballot goes in another box. No reason why we couldn't have 20 boxes if we also voted for issues directly.

Also in local elections we can write in other people and give people on the ballot an "extra" vote for which we use a pen (but this is voluntary and I assume most don't bother).