Domenico,
kindly specify what exactly you are trying to do.
Example: at one of my customers, they need to go via a certain location X when they come from Germany and go to Norway. To make the system generate 2 stages one from the departure to X and one from X to the end Point, I find it most comfortable to use default routes. It is master data and NOT an enhancement. You define a default route from Zone Germany to x and from x to Zone Norway.
When generating the FU, the System will check what is the zone of the departure point and what is the zone of the Arrival Point and default 2 stages. Now, you can create a Manual freight order for each stage.
Not sure if this answers your question, let me know.
Regards
Petra