WordPress is great at providing a robust system for managing content. However, one of it’s pain points is trying to create a relationship between posts (i.e. post to post relationship). Yes there’s taxonomies but sometimes you really want to tie specific posts to other specific posts. This gets more complicated when you have three (or more) different post types that need to be related to each other. And each one of these post types need to relate to multiple individual posts of the other post types.
Enter the fantastic plugin CPT-onomies.
In a nutshell, CPT-onomies allows you to treat a post as a custom taxonomy, allowing you to link posts together as if each post title was a term in the custom taxonomy.
CPT-onomies also makes it easy to create and manage custom post types and does a great job of walking you through how this is actually done. It actually explains what the options are and how WordPress uses them. But you can create your CPTs (Custom Post Types) with other tools (or by hand) if you want and just let CPT-onomies do it’s magic. Another nice thing is that CPT-onomies follows, as much as possible, the existing structure of taxonomies within WordPress. Functions are nearly identical to the built-in taxonomy functions so its easy to incorporate in your templates.
So yeah – if you need to build out more complex relationships between posts, beyond the standard taxonomy relationships, take a look at CPT-onomies.