How to identify a returning user in LMS with a variable

Hi there!

I'm a beginner (maybe intermediate) user in Storyline 360. I'd love some help with the settings in a course I'm building...

I'm building a course that's hosted in an LMS system and we're recording grades. The course has 8 video segments with 8 separate multiple choice questions that follow the segments. The customer would like to force the users to watch each segment the first time through, but not on subsequent times. They also want the course to only allow 3 attempts at a final grade and then lock/disable the course.

I'm having trouble having these settings get along...

• I previously set up a retry button on the Results slide that disables after 3 attempts. The problem was: it only would record 1 attempt/1 grade in the LMS if the user used the "retry" button for three attempts.
• I've removed the retry button and now am forcing the user to restart the course in the LMS for a fresh attempt so as to not botch the grades.
• However, now it's forcing the user to rewatch the video segments on each additional attempt.

Is there a way for me to reference a student/user ID so that I can allow the returning users to bypass the videos segments on additional attempts? I'd love to disable the "next" button on a video, and then maybe add a condition to the trigger that identifies returning LMS users.

Note: I've only ever read about API calls and Javascript work within Storyline in these forums. I'm wondering if there's something I could do there to set a variable in Storyline?