It's possible to add a JModelList functionalities in JModelItem? for instance on my component site part a "specific item" is associated with files whereis you can add the files for a specific item using another component. once I selected that Item in the menu just like how we did in adding our article in the frontend. once you navigate to the "Item" you see the list of files associated with the item? however if I didn't add the functionality of the JModelList pagination would not work. how I can add the functionalities of JModelList in JModelItem?
Looking on you current design I advice you to do vice versa - use
JModelList as a base class and add functionality of
JModelItem if you will need it.
Or you can create the class for files extending
JModelList and get the items and pagination from there.
Anyway you can do anything you want. It is not obligate to follow the rules of CMS. You are the developer and architect.