Multiple Back to Back Orders

 Hi,

Here is the multiple back to back order I am performing  - 

1.Customer places order in S1 OU & INV1 Inventory org for Item A

2. The ITEM A  has a transfer from Sourcing rule setup and its a ATO item.

3.On progressing the order, the internal requisition is created 

4..IR is turned into ISO and gets shipped from INV2(Inventory org2)

5.On progressing this ISO, the line changes to external req opened..eventhough the item is not an ATO item in INV2.

6.I have sufficient on hand in INV2 irrespective of that its again creating Purchase req..

Is it possible to restrict the ISO and make the  item gets shipped from INV2 org..??