I’m wanting to use custom fields in a way that allows me to add a Page ID to a field in the WordPress admin and have that Page ID used to display the siblings of that ID. Not really sure the best approach for this, any help would be appreciated.
You would use a post object field and then you would use the value of that field to do a query to get all posts what have the same value. https://www.advancedcustomfields.com/resources/query-posts-custom-fields/
