Subpages for plugins

Hey!

I am trying to build a backend for a webshop in WordPress, and I have run into a problem. I have created an entry in the menu with this structure:

Webshop
– Overview
– List of orders

Is there any way I can make a seperate page for viewing a specific order in detail without adding it to the menu?

I can’t really seem to figure out how to do this as linking to a specific file doesn’t get it wrapped into the admin backend.