I have a customer ... Customer XXX that recieves a list of parts from vendor ZZZ

Customer XXX resale is lower than our standard cost from vendor ZZZ.

So whenever we turn customer XXX's sales quotes into an actual order, the cost price of the part does not allow us to update the cost in Sales Order entry to these "special" costs that we aquired from Vendor ZZZ, so it looks like a drastic loss on the accounting side of the order. 

How can I set up these specific parts for this customer (because the cost recieved is not available for any other puchases against these parts .. only purchases applied to this customer and the vendor is told the quote reference number when we order them ... )

I can set up the customer pricing to default to the price that we quoted the customer, but can't seem to reference the part COST to not show a large loss??

Which files would I need to update in order for it all to fall together ... ??

Hope someone can help ..

Thanks