I have successfully created a quick mockup of a form that allows a user to submit a review and connect it (set the relationship) with an organisation, , showing a dropdown of organisations to connect to:
[mb_frontend_form id='review-relationship_relationships_to' post_fields='title' post_type='review']
However, when I add a custom fields group id into the mix, nothing happens:
[mb_frontend_form id='review-relationship_relationships_to, review-fields' post_fields='title' post_type='review']
If I put 'review-fields' before 'review-relationship_relationship_to', only the review fields display, and the review relationship dropdown disappears:
[mb_frontend_form id='review-fields, review-relationship_relationships_to, review-fields' post_fields='title' post_type='review']
I thought we could return multiple meta boxes by inserting their IDs separated by a comma?