Design pattern suggestion for system with multiple scenarios

I am working on a scenario, where I have a list of orders.
Order DTO:

public class Order{
  private int orderId;
  private String orderType;
  private String orderingSystem;

  ... GETTER & SETTERS
}

• orderTypes can have NEW,EXCHANGE,RETURN possible values.
• orderingSystem can have INTERNAL_SYSTEM, EXTERNAL_SYSTEM possible values.

Based on the orderType & orderingSystem I have to process every order.

Common business to be applied on every order:

1. Order validation.
2. Order Enrichment
3. Execute ordering algorithm(will vary on the orderType & orderingSystem).
4. Finally persist the list of processed orders into DB.

Possible combinations can be

1. NEW order with INTERNAL_SYSTEM
2. NEW order with EXTERNAL_SYSTEM
3. EXCHANGE order with INTERNAL_SYSTEM
4. EXCHANGE order with EXTERNAL_SYSTEM
   & so on..

How can I design my application to accommodate each and every possible combination?