As you’re probably already aware, WordPress is designed with two main content types: Pages and Posts (see also http://en.support.wordpress.com/post-vs-page/)
The very design of Posts is to not be hierarchical. And the nature of Pages is to be hierarchical. Posts are to be part of a blog. Blogs are almost always ad-hoc in organization. Thus there needs to be many ways to navigate those posts. Plus there isn’t a parent > child relationship. Each new post is considered it’s own entity, though it can be tagged or categorized to create relationships with other posts.
Another way to think of it is:
Posts = Blog
Pages = CMS
It’s important to understand that since you’re using a pre-existing CMS, you are taking a Bottom Up approach. This means if the core functionality doesn’t work for you, it’s best to find another solution that meets your needs rather than try to hack the basic principles of a CMS that doesn’t work the way you want it to.
You can create Categories to provide some pseudo-hierarchicy to posts. With some of these core concepts, it’s easiest to try and use best practices. That will also create better results long-term. Making it easier to maintain, update and modify.
WordPress is also designed for SEO. I realize for an intranet that’s of no use to use, but again that’s what it’s designed to do. Because of this, it doesn’t allow you to duplicate content unless you force it to.
What I would do is:
- Create pages as main containers of ideas and concepts
- Link those pages to the posts (or I wouldn’t even put the info in posts to begin with, but pages. For me, if it’s not part of the blog, it’s not a Post, it’s a Page.)
- Never link to the same content from multiple places within the main navigation.
I would only ever put the content in one place and I would organize the content so that that is the case, and that it only ends up in the navigation one time. It’s okay to have a page reference other pages.