Different pricing on BPA for back to back or drop ship orders

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Our company negotiates pricing with the vendor based on specific client contract or sales orders. So one part could be procured from a vendor with a price different than the same part with same vendor if the client on the sales order is different. We want to automate PO creation for these back to back and drop ship orders by using BPA and enabling auto PO creation. However, I am not aware of an option that allows us to define different price for different BPAs for the same part/supplier and have the system pick the correct BPA when fulfilling those