Here is my scenario and I am not a coder so I will try to give as much detail as I can. I even tried getting different AI's to chime in on possible ways to do what I want.
Maybe my approach needs to be changed.
I have a directory website of restaurants. That CPT is up and running fine with all the needed taxonomies and fields all setup.
I wanted to add menus for each of the restaurants. So I had two options, just add more fields and field groups as needed to the already existing restaurant CPT, or, create a new CPT for menus and create a relationship between the two.
I chose to create a CPT for menus. Within each menu I added the main few fields needed as well as a cloneable group for the individual menu items.
Went to the relationships and created a 1-to-1 relationship from menus to restaurants.
So far, so good.
But I cannot for the life of me figure out how to connect a relationship field as that is not any kind of type of field that I can find, nor is it an option anywhere I can find. In my menus CPT I set the restaurant name to be a post type and to be connected to the restaurants CPT but can't single out any specific fields to be pulled in and used there. I want the restaurant name to be pulled into the menus to be able to maintain ownership as being only for that restaurant.
So, am I missing something? Or should I have gone with the option of just adding cloneable groups within cloneable groups in the restaurants CPT?
Any help would be greatly appreciated.
The relationship isn't a custom field, its data doesn't save to the default table wp_postmeta, it is saved to a custom table wp_mb_relationships.
To get and display the relation posts, you need to use the code, following the documentation https://docs.metabox.io/extensions/mb-relationships/