Multiple Quiz Branching course

I have a request from an internal customer who wants a course set up from 4 different courses.  These courses cater to four different groups (A, B, C, D).  What he would like is A, B, C, D to start the course but after the first quiz, Group A would receive credit for a passing score and be able to leave the course with a completion status sent to LMS.  As the course progresses he would like the same functionality for group B, C, and D.  

I know about how to set up multiple quizzes with cumulative results slide at the end from multiple results slides but I have never had this sort of request before.  Is this something that is possible as the Publish feature asks for a Results slide to report on.  Will a results slide that requires 90% from all results slide calculate based on the quizzes not required as 0% on an average?  So, if there are 4 quizzes and the person in A completes a 100% for the first (and only required) quiz, would the final results slide calculate, say, a 25% based on non answered questions?