Hi Elliot,
I’ve started to (attempt) to build a custom field for this, here’s the interface I have so far –> http://cl.ly/image/0B1v1y0t4145
It uses acf_field_group::get_field_groups(array()) to fetch the current field groups, excludes the field group you’re currently editing, and then displays them in the select element.
I’m not sure how far I’ll get with making a custom field… if anything comes of it I’ll be sure to share the code.
