Internal Purchase Order Through Interfaces?

Hello

We are going to integrate a distribution center 3rd party software with Oracle EBS. The DC software creates internal purchase order to our manufacturing plants for finished goods. In our EBS instance, both plants and DCs are setup as separate inventory organizations.

Can someone please explain how the internal purchase orders can be mapped to Oracle EBS without internal order-internal requisition cycle. Obviously plants don't generate any sales order so the cycle can not work!

Thanks

Roger