Link a custom post type child to a parent using dropdown

I would add a custom taxonomy called “wine” as well. You can use this taxonomy to associate reviews about the same wine and also to associate the “wine” custom post with the taxonomy. Then you can run a query to get all “review” posts that share the “pinot” term in the “wine” taxonomy, for example.

This makes it easier to group posts, custom posts, and pages without needing to know $post->ID for anything.

Justin Tadlock has written a fantastic explanation of custom taxonomies if you need a place to start …