Hi Dev,
I am not clear with your requirement, but i am giving normal partner function explanation, it might helpful.
Always we will have only one partner function field in BTPartners context node, the value you are assigning to the partner function will vary based on type of partner function.
Suppose for example sold to party partner function will be assigned with 00000001 and ship to party will be assigned with 00000002.
You can fine the partner function id in SPRO->customer relationship management->Basic function->partner processing->Define partner functions
Whatever partner number you will enter across the partner function that value would be the assigned to the partner function. Its like partner function --> Partner number in BTPartners context node.
You can use the same partner function field for your own partner function as well by renaming the field and check the context node of sold to party attribute in your view.
Best Regards,
Dharmakasi.