Set up routes in a chain

Welcome to the forum @kjetil !

Gugi’s approach with a storage subscriber will work.
Another option is to use a HTTP Transformer to send data between systems in one route.

With a HTTP Transformer combined with conditional transformer you could check if ‘manufacturer X’ exists, if yes continue with transferring the product.
If no create ‘manufacturer X’ and then transfer the product.

A request with a HTTP Transformer will not count towards the consumed tasks which is a nice benefit.

Example

This shared afas configuration has a transformer that uses the explained principle for customers: AFAS Profit [Sales Order, Customer]