Hi TW,
thanks for the clarification (because of this would have been a multi-customer warehouse, things would look a little bit different).
"For example, DHL warehouse; for every customer doors are fixed. Could be for several reasons (special belt doors for some customers etc. etc.) Thus if SP / SH is C1, then the pick up should be from ST1 (which is near D1). On the other hand, when SP / SH is C10, then the pick up should happen from ST10 (which is near D10)"
Still I must say.... strange scenario. Because then you would have to consider this already during putaway. When the material comes you would need to know how much you would need for C1 and for C10 later, to find the ideal putaway bin. Now I assume you have no customer / sales order specific stock, because that would cover it.
If not: there is no standard solution for it. BAdi is the way to go. The door / staging area to where the material goes to, is not part of the determination. Except of course you use something else to find different warehouse process types, that would influence your source determination, but also these are not customer dependent.
Brgds
Juergen