Add submenu item for custom post type

I’m looking for a way to add a submenu item to my own menu which will load the CPT UI as normal. I understand how to add the CPT menu as it’s own admin menu entry but I want it placed into an existing menu of my own. It organizes the workflow better this way. However I am drawing a blank trying to find a method to load the edit UI for my post type. Clues anyone ?

TIA
Erik