sumifs with vlookups? offsets?

What I need to do seemed simple at first..but then rapidly became hard.
Class Section People Fees
Gold A 0 0.25
Gold A 76 0.15
Gold B 0 0.25
Gold B 76 0.15


I have another table that contains Class, Section, People in it. When it calculates the final fees column, if the class is gold, and the section is A, and if the total number of People upto to that point is more than 0 but less than 76, then the fees is 0.25, if it is greater than 76, then it is 0.15.

So i need to look up two values and do a sumif on the third, and pull out the corresponding fees number..phew. I hope this makes sense. Any ideas for this one?