Courses within a Course

Hello, I think my question has to do with scenes and branching but I am a total newbie so could use any help available.
I am using Storyline 3.
I have been asked to create a course that starts with general content applicable to all users. Then, a selection must be made by the user to direct them to the content within the course that is specific to their category.
There are to be three categories.
Once the user makes the selection that directs them to the content related to their category, they will follow that path to the end of the course and will be prevented from following the other two "paths".
There also needs to be a quiz and a results slide at the end of each "path".
Kind of a "choose your own adventure" type of set-up, except the user is limited to only one "adventure".

I hope this makes sense and I'm eager to hear from anyone who knows about or has experience with this. Hopefully it is possible.

Thanks!