Requiring a pass mark to continue to next section

I'm wondering if anyone has some ideas that can help me get past a roadblock.

I have a course that consists of several .story files (referred to as modules in my LMS). Each one has a quiz, followed by the result slide, then a summary slide with two layers--one stating 'you still need to pass the quiz' if they failed, and the other saying 'continue to the next module'.

I've set up the restrictions that Jeanette suggested in the following tutorial using a true/false variable to regulate whether the summary slide is seen (and which layer on it is visible):

http://www.articulate.com/support/kb_article.php?product=st1&id=66anx269bg95

Here's the catch. I've restricted progress through the LMS-based modules so that all slides on the previous module need to be viewed before moving on to the next one. With the current setup, even reaching the 'you still need to pass the quiz' layer on the summary slide means that a learner can exit this module and continue on the the now-unlocked next one--they have, after all, seen the slide.

Setting up a branch to either a Success or a Failure slide won't work; if someone passes, they won't see the Failure slide and the next module won't be unlocked (based on the number of slides viewed).

Does anyone have a suggestion for how to keep the next module from being unlocked for someone who failed the quiz, but allow someone who passed to continue on?

Thanks!

Allan