Sum x most recent occurences

[mrbreeze]

I'm trying to sum the four most recent occurences based on a given critera and then be able to autofill for a large dataset.

Please refer to the attached spreadsheet which will hopefully make the problem more obvious. I have the date in column A, a colour randomly listed in column B and a random figure in column C. In column D, for each row, I want the total figure from column C for the 4 most recent occurences from the date in column A of the colour given in column B. I have manually filled the first 5 rows for column D so it can be seen what I am after. I want to be able to autofill as my real dataset is very large.

Im not gonna lie, I don't really know where to start with this one... any help much appreciated!