Transferring New Items Between Business Partners In SCM

Continuing the previous topic about sending outbounds documents from one base to another I found out an interesting point concerning the transferring information on new items between two or more bases.

Say, we have two business partners which are called Customer and Vendor. The SCM between them function very simply.

When Customer wants to get some needed goods purchase orders (Purchase Requisitions) with appropriate positions (Items) are sent to Vendor.

But if Vendor start producing some new goods how can these positions (Items) be sent to Customer in order to synchronize their common space of Items table?