‘Import Craft’ option in the Designer

In the Vizzy Program Environment you have next to the 'Load Program' Button the option to import another Program to combine them.
It would be really helpful if you had something similar in the Craft Designer Environment.
In my Case for example I have a Craft with 3 Parts (Stages). The upper Part I call the ‘Main Shuttle', which I also have saved as a separate Craft independently. I recently changed quite a lot of Details at it and want to have those changes also applied on the bigger Craft.
I don’t remember every Detail and would have to switch between them constantly to copy everything. This would take me hours. If I could just import the Main Shuttle to the bigger Craft I could easily replace those two Parts.