My situation is similar to what was asked in this thread: https://www.odoo.com/forum/help-1/question/how-to-add-product-with-return-able-case-3202
However, what I want, in addition to what was asked, is when a Sales Order is created it should create two transfers automatically: an OUT Transfer(default behavior) will contain the kit(water + bottle) for delivery and an IN Transfer which will contain the empty bottle. How do I setup odoo to do this? Or if not possible, could you point me on what code should I modify to enable this kind of behavior? Thanks.