Dennis @ PerfectForms
You also can consider using parent-child relationships. You could make the three quizzes all child forms that get parameters from the parent and report back to the parent at a certain workflow stage. This will give you the advantage of giving the parent and children their own individual workflows, but retaining the ability to be conditional on one another. We have a parent child interactive example in our help guide: http://www.perfectforms.com/Documentation/manual/html/?fl_parent_and_child_forms_example.htm.
We also have training videos on parent child relationships: http://www.perfectforms.com/training_videos.php