Partner function ER (Employee responsible) should required in sale order in completion procedure.

Dear Friends,

I want to set Partner function ER (Employee responsible) should required in sale order item level in completion procedure.So with out Partner (ER)system should not save the order.I want to know whether it is possible by standard r/3 or enhancement?

I searched the forum but no relevant answer i found.Help me to make it possible.

Thanks&regards,

Ravikumar.Ravooru