There are a couple of problems that arise here. First, shipping costs will consist of two shipments. Second, how is the order going to be dispatched from different vendors? Third, what if you need to use more carriers?
Shopify Shipping does not offer multi-vendor shipping. So, that is not an option here. A key to managing multi-vendor shipping efficiently is a third-party Shopify shipping app. Calcurates can help you automate the whole multi-vendor shipping process. Our multi-origin shipping feature
includes origin-based shipping methods, origin selection based on the stock quantity and distance, and more.