Post parent highlighted in nav

I have all posts displaying on a page: “Resources”:
https://www.500.uk.com/resources/

The page “Resources” where posts are displayed, is highlighted with a list class, but when you go into a post (single.php) I can’t seem to find a way to keep “Resources” highlighted.

What I want is for every post to look like it is in the resources section. I cannot manualy do this as I need it to be a dynamic generated menu list.

Is there any way I can do this? Can I make resources the parent for every post?

Another note: I have achieved this with Pages by using the Fold Page List plug-in (https://www.webspaceworks.com/resources/wordpress/30/) but it doesn’t seem to work for posts.

Please help.