There are three ways you can go about this:
- Add custom rewrite rules that will indicate which neighborhood the places templates should pull from, add logic to alter the query to only load those places, and add meta fields to link the places to a neighborhood (lots of work)
- Add a “Neighborhood” taxonomy for the places (has redundant data)
- Merge the post types into one hierarchical post type (not well organized)
Personally, I would go with (2). If you decide to go that route, it would be as simple as
- Register your custom taxonomy
- Leveraging the template hierarchy, add custom templates for your places, e.g.
taxonomy-neighborhood.php
While this does have some data redundancy (individual neighborhoods will be both posts in a post type as well as terms in a taxonomy), that’s rectifiable. The key to making this work well is convention over configuration: make sure that all the neighborhood slugs are identical in the post and term.
If it were me, I would then hook into the save_post process and make it so that any time a neighborhood is added or its slug edited, a term is also added or edited behind-the-scenes. I would also remove the term pages from the admin panel so the editors can’t add/edit the terms, and only have access to the posts.