Need help on the following :

I have a list of countries which is separated into Group A, B and C. Each of
these countries return to a value based on certain conditions e.g

Conditions | Country Group A | Country Group B | Country Group C
Heavy | 1 | 2 |
3
Medium | 2 | 3 |
4
Light | 3 | 4 |
5

I have set up a vlookup function for this. However, there is an exception,
China which falls under Group B should return 4 for all conditions. India
which is in Group C should return 5 for all conditions.

What formula can I use? Thank you.