Need help with SKU for variations with 2 attributes

So I am having an issue setting my SKUs and I was wondering what I should do.

So I have two attributes that I need customers to select, Model, and Size.

I only have different SKUs for Size, however, it does not let me input the same SKU for all of the different models under a particular size. What should I do in this situation?

Ex, I have products like this:

SKU 1SS: Size S, Model 1
SKU 1SS: Size S, Model 6
SKU 1SS: Size S, Model 9
SKU 1DD: Size M, Model 3
SKU 1DD: Size M, Model 5
SKU 1DD: Size M, Model 4
SKU 1EE: Size L, Model 7
SKU 1EE: Size L, Model 3

How can I replicate this in woocommerce? Or is this not possible?