HOW TO CALCULATE AGGREGATE OF STUDENT'S MARKS

In creating an excel app to calculate the aggregate for students in their exams as used by WAEC to determine the student aggregate in BECE . The Excel has to select Six Subjects from Nine Subjects, with Four being compulsory and Two other best. I want an excel formular that will add the grade value of four compulsory subjects : English, Maths, Science, Social. And then automatically select 2 other subjects from the rest with best grade value.



For Instance, If a student has the following result:

1. English - 2

2. Maths - 1

3. Science - 1

4. Social - 2

5. ICT - 3

6. BDT - 3

7. RME - 1

8. French - 2

9. Twi - 2



I want a formular for this calculation :

English(2)+Maths(1)+Science(1)+Social(2) and randomly select best other two subjects from the rest : RME(1)+French(2) = 10



Kindly help me.