The only way to achieve what you want is to merge Balenzino-Mosti into your own route and delete everything that you don't need. Tedious but that's all you got for now.
Alternatively, but basically the same thing:
Make a copy of the route (by cloning it in Content Manager for example or just saving it under a different name). Edit the route and delete everything you don't want. Now merge what you have left into the route you like to have it in.
