IDoc ORDERS - Control Agent responsible

Is there a way to control who will be receiving a work item based on the sales organization in IDoc type ORDERS?

We have some Customers extended to multiple sales organizations.

We would have 1 CSR per sales organization.

However, in WE20, the post processing permitted agent is Customer specific.

We are presently maintaining a position as agent type in WE20.

We assign all possible CSR's user ID to this position via PPOM.

As a result, when a work item is generated, ALL CSRs are getting a work item (evern when it does not belong to them).

How could we be more specific and, based on the sales organization inside the IDoc, only send the work item to the business workplace of the affected CSR ?

We are on ECC5

Thank you for your assistance,

Arnaud