Author section completely hidden for public

Oi there.

So I’ve been searching around for hours and haven’t found a solution to my problem yet.
I’m making this blog site which has a few predefined authors. I need to be able to make posts readable for these authors only. The way I’ve tried to come around this issue is by making the posts private. The problem then is that they’ll go into the same big feed as all the other posts. So i’ve made a category for these posts and then set the category into the main menu. The problem then is that the public will be able to see the category in the menu but not the posts.

so basically is there any way to hide a section in the menu from the public or does anyone have a suggestion/plug-in that can help me out?

Thanks in advance!