Show specific posts (CPTs) on specific subpages

Hey guys,
I’ve searched for hours but I can’t find a solution:

My next website has this structure:

– Home (Page)
– Departments (Page)
– – Department A
– – – News (Page with Custom Post Type)
– – – Events (Page with Custom Post Type)
– – – About (Page)
– – Department B (see A…)
– – – …

Every department should have 1 author. The author of Department A should be able to only change/add and see pages or posts of Department A in the admin area. A new post of Author A should be assigned automatically to Department A. (no need to manually choose Department A as category or similar).

A user with the role “author” can only see his own posts. So this will do the trick in the admin area. But I struggle with how to display a list of Custom Post Types (e.g. News posts of Author A) at the news-page of Department A.

Any ideas or best practice tips?

THANKS A LOT!