Auto Populate Contacts Custom Field (Cf.SalespersonAssigned) data to Sales order Default Field (Salesperson) when same customer is selected while preparing salesorder

Auto Populate Contacts Custom Field (Cf.SalespersonAssigned) data to Sales order Default Field (Salesperson) when same customer is selected while preparing salesorder

Auto Populate Contacts Custom Field (Cf.SalespersonAssigned) data to Sales order Default Field (Salesperson) when same customer is selected while preparing salesorder.

For Eg.
Customer A has custom field "Salesperson Assigned" = Andrew

I am preparing a Sales Order for Customer A.
Instead of selecting Andrew in Salesperson (Sales Order Module), It should auto populate data from Customer A's custom field "Salesperson Assigned".