Hi Paul,

All users have access to all of the courses on Khan Academy, so there's not a way to change the grade level for a specific group of students per se.

If you would like to assign content from more than one course, you can do so by going to the Settings tab in your class. Here, click the Edit Courses button to add or remove courses from your class. Then, on the Assign tab you can use the course dropdown to select which course you want to assign content from. When creating the assignment, uncheck "All Students" and then select only the students who should receive the assignment from that grade level.

If you're using the Mastery Goals, you can also assign a mastery goal from a different course using the same manner as described above. When creating the goal, just make sure you only select the group of students who should receive that goal. You can also edit any existing goals to remove those students from the previous grade levels if needed.

I hope this helps! Please let me know if you have any additional questions!