As for the source you can either just make seperate sources or edit a source and click on the ‘add’ button which will make all the file paths show up as if there contents were in the same base folder. Either way the actual file paths will still be stored in the database so you can use them as a way of separating off the content. To make separate menu items it depends on what skin your using. If your using the OSMC skin then there is a couple different ways on how to accomplish this task [here].