I inspected the navigations, they all have different IDs and css classes, so yes, if you want to create more of them, you’ll need to create more hooks individually for different pages.
For CSS, you could use ,
to separate css classes and the css you write below will apply to them all, for example:
.discrimination-nav .menu-discrimination-container ul li.current_page_item a, .unfairdismissal-nav .menu-unfair-dismissal-container ul li.current_page_item a {
background-color: #f58538;
}