Tracking training completion

Is there a way to track completion of the training by viewing of a particular slide?  I have multiple quizzes in the training (depending on which track the user follows) and the user doesn't have to take all of them.  But, the training is set up so they cannot reach the final slide until they have successfully passed a quiz in each section. (5 sections - each a specific topic with two different tracks in each). I don't think I can make a combination result slide, since they don't have to take every quiz.  But, I don't want to track by # of slides either, since the number viewed will depend on which track they use. (Do quiz questions count?  They take answer the same number of questions no matter which quiz unless they re-take a quiz.  I don't allow them to progress until they have 100% on each quiz, but allow them to retake as often as necessary).  Any suggestions on the best way to set up the tracking?