How can I integrate a new system to a design scheme I previously created? This is a follow-up to a question I wrote a while ago, for reference, you can look it up here.  

I've developed a curriculum based database scheme that looks like this(Thanks Joel Brown)


Now that a new educational system is introduced(while the old one is still not "deprecated") I have been looking for a way to integrate both curriculum systems together without creating a whole new different system; As the two systems are fundamentally different, this have been quite a challenge for me.

Here's a picture describing the new system . . .  

  

(English level 1, 2, and 3 are classified as courses)  

See, the new system removes the whole grades system. A jr. high school student can enroll in the exact same course(English level 3, for example) as a sr. high school student.   

Is there a way to make those two systems work with my current design scheme? Or should I create a whole new scheme for the new system?
Would it not solve your problem to redefine the GRADE_LEVEL table such that it contains either the grade of a course or the level of the course (which ever applies)?

The rows in GRADE_LEVEL could contain values such as:

GRADE 7
GRADE 8
GRADE 9
GRADE 10
GRADE 11
GRADE 12
LEVEL 1
LEVEL 2
LEVEL 3


You might consider adding a partitioning attribute to the GRADE_LEVEL table that would indicate which educational system is being applied.  This may be helpful for some of your application logic that might need to apply different processing depending on which system is in use for a given COURSE.