Quest supports merging several sections of a class into a primary Quest course, using associated uniques to keep the sections sorted in the class roster and grade book. You simply enter the associated uniques when you create the course, or add them to the course later on the "Course Settings" page.
Students then use the appropriate associated unique when enrolling in the course. Alternatively, if you are a non-UT instructor, you can create auto-enroll links specific to each associated unique for direct enrollment of your students. For more information about auto-enroll links please visit this page.