Requisition for transfer material

 Hi:

I have the next scenario:

The business is a bank, it has just one inventory organization, but a lot of sites( these sites dont exist like inventory organizations, just like locations).

Then when the user makes a requisition from iprocurement, the goal is that the  requisition act like an internal requisition if stock exists in the Inventory organization, or act like a purchase requisition if there is none stock in the inventory organization.

It is possible to do?.

Thanks