We would like to make someone outside our organization responsible for shipment and want to do this via tasks. This/these person(s) are not working with Odoo and we don't want to give them access to our Odoo environment.

The idea is as follows:
1. Order is coming in

2. Tasks are made (automatically)

3. Manufacturing task (can be order overview), including shipment details, is send to manufacturing company

4. Finished products are shipped by manufacturing company to client

5. Person @ manufacturing company, responsible for shipment, sets task as done (and/or replies comments) 

6. We mark order as finished

How can we achieve this?