Forcing Voters to vote for 2 options

In a short film competition, we want the audience to vote for their two favourite choices to ensure that they won't just vote for their own favourite film. Is it possible (for example in Dot Voting) to hide the Submit button from participants until they have voted for exactly two options?

At the moment it is not possible to force voters to cast all dots. We already have this on our to do list, but it is not yet planned for development. So I can not tell you when this will be ready. I keep you updated here.