Hey! You're on the right track with copying the XML data, but there's one small, crucial step you're missing!
When you duplicate the network and paste the XML into the new file, you have to open the new .xml file in a text editor and change the unique ID/name right at the top of the file.
The HISE compiler uses that unique identifier to distinguish the network. If two files have the exact same ID, HISE gets confused and only loads the first one it finds.

Just change the name/ID string in the duplicated file, save it, and it should pop right up! Hope that helps!