Shipping the item from the location which has the positive qty

Hello,

We normally use the program R42500 to ship the item. Most the time, the sales orders are entered with location 'A', but the location B has qty. What we have to do is to transfer the qty from B to A and then run R42500. Is there any setup to deduct the qty from location B without change the location to B in the sales order?

Thank you

Nichole