Thanks Juerg..
So please tell me if following will work:
I will create four derived flows (based on above 4 combination) for which 4 derivation rules will be created. Original flow will be 1500 and 1510.
We will assign above 4 flows to one derivation rule and that derivation rule will be assigned to that business partner.
We will create one Z Table for combination of commodity, exchange and derived flow. While posting transaction, system will search commodity, exchange and it will pick up that derived flow only (or delete other derived flows not relevant) in FTR_CREATE.
I am asking for this possibility. Because at present (without user exit), all the flows are coming by default in FTR_CREATE. When i delete other three flows and save the transaction, system automatically brings and post the deleted derived flows in transactions.
Please let me know.