mmmm first question: Why?
The nature of the backup may not allow you to do what you want anyway. In a very allegorical way this is how it works: What you see in a course is the shell plus the data, files, resources, activities and so on, everything. Click a part and Moodle does what it is supposed to do. When you backup, what you get is the data, files, resources, activities and so on, everything, but not the shell. The backup file is constructed in a standardised way, with the same folders, same root files as every other Moodle backup file. You can look at this yourself, change the file extension of a backup file from .mbz to .zip. Unzip the file to a clean folder, then open the Moodle.xml file in a text editor. I use TextPad because it works for me, it is easily configured to save files in the UTF-8 format. At this point, if you do not understand xml code, I seriously suggest you forget the idea. If you dio understand xml code, then I suggest you forget the whole idea and do something different.