Quizmaker - Working with follow-up questions

Hi

I've created a quiz consisting of a few question groups.  The questions in those groups are randomised and I've set it up to include all questions.  The navigation menu is also showing.

In one of the groups, I have three questions that are locked together.  The first question is a "Yes / No" question which branches to either of the other two "follow-up" questions, depending on the answer given.  The trouble that I'm having is that both of these follow-up questions are appearing in the menu and currently this means that the user can skip the primary question and jump to either of the secondary questions.

How can I set this so that the users can only access the follow-up questions via the primary question?

I would also like to have it so that by the end of the quiz the user has to have answered either one or the other follow-up question and is not required to answer both.  Is this possible?

- Paul