Thanks for your question and for taking the time to find an earlier topic along similar lines. You may also be interested in these related topics:
Possible to add ACF custom fields to the Assistant screen?
Advanced Custom Fields repeater
The short answer is “yes, sort of”. I have done some work with Advanced Custom Fields and there are two MLA examples in the /media-library-assistant/examples directory; mla-acf-checkbox-example.php.txt and mla-advanced-custom-fields-example.php.txt. Perhaps one of them can be adapted to your application.
ACF Relationship fields are stored in the postmeta table as an array of post/page/media “object ids”. If you know the ID values of the objects you could write some code to present them and update them as a comma-separated list. That’s the way they are displayed in the Media/Assistant submenu table if you add the field to that screen. Supporting the scrolling list and search box functions provided by ACF on the Edit Media screen would be much more complex.
Have a look at the earlier topics and the example plugins. I will leave this topic unresolved until I hear back from you with your progress, problems and further questions. Thanks for your interest in the plugin.
