Multiple random questions on registration (anti-spam)

[Black Tiger]

For extra anti-spam I make use of the build in "Question and Answer" challenge.

However, I can't define anywhere how many questions should be asked. At this moment I've got 7 questions in there from which I like to have asked 3 of them randomly on registration.

When testing registrations for another problem, unfortunately only 1 of those questions is asked and it's also often the first one.

Is there an option to have a custom set (for example 3) question/answer challenges done on registration? Or if not, I would like to put this in as a feature request.