Exchange sales order from SAP CRM to SAP S4

Hi Guru,

We're going to exchange sales order from SAP CRM to SAP S4.

We know that we have to setting Transaction types, Item categories, Item category determinations equals in both systems.

about number ranges, they must be equals in SAP CRM and SAP S4. But we don't know if number ranges of SAP CRM should be internal and number ranges of SAP S4 should be external?

Best regards,