How to use SUMIF when using Conditional Formatting

Sorry about that. So, what I have done in the new file is I have basically, fulfilled 144 + 72 = 216 worth of orders,
as that is the maximum amount of orders that can be fulfilled (based on stock which 216).

I highlighted Buyer 10 and Buyer and Buyer 17's orders for Product X. I am trying to find out
how I could do this with a conditional formatting rule (if this is possible) + if I can do this
without having to sort the row from smallest to largest or anything like that. Is that a bit clearer?