You use the administration cross tab to create links between administrations. This way you can book hours in one administration that are then accounted for on a production order in the other administration.

Example entry 'Internal Invoicing' in the journals 'Hours', 'Sales', and 'Purchase' following the action 'Internal Invoicing of hours in the source administration'. Transaction types 07 Hours, 03 Sales Cost Price, 14 Manual Sales Invoice, and 09 Purchase Invoice.