Salesman for a customer (Sales responsible)

Hi,

I have a question about assigning a Sales responsible person to a customer as defualt

E.g Customer C001 has been assigned to Salesman S01 and when ever we make a Sales order  this Salesperson should automatically appear on the Sales Order as Sales Resposible and if needed we can change at the sales order level, but the question is How can i store this informaiton at Customer level?

Or any other work around?

My only requiirement is i should have a default salesman for a customer which i can chage at transaction level if needed,

regards