Can I add sub-pages to an index and/or project pages?

I have an index page with project pages. I'd like to add further subpages to each of those project pages. Is that possible? 

What I intend to do is to link blocks/sections to another page. i.e. display a picture of a dish and link that to its own page where the reader finds the recipe. I do not wish for that "final destination" to be displayed in the header/navigation menu. 

You can put sub pages into the unlinked section of your site, they will not appear on the nav bar. Images and text links in your project pages can direct visitors to those subpages.