Jez,
If I am understanding you correctly, you have a Custom Field in CPT b and you want CPT a to have access to the options that are selected?
To target a specific field in a CPT you would change this block
$args = array(
'public' => true
);
$post_types = get_post_types($args);
foreach ($post_types as $post_type) {
if ($post_type !== 'attachment' && $post_type !== 'page')
$field['choices'][$post_type] = ucfirst($post_type);
}
to something like
$cpt_custom_field = get_field($cpt_id, 'the_name_of_the_specific_field');
foreach ($cpt_custom_field['choices'] as $value=>$label) {
$field['choices'][ $value ] = [ $label ];
}
Or whatever you want to replace the information with. Nested repeater fields are slightly more complicated, but code examples for that are in the docs. You could create a colors array and assign the select to those, you can grab all post names from a CPT and assign those, etc. You just need to change the above code to match what you are loading into the choices field.
