Hear me out here as this gets complicated…
I have a custom taxonomy called student. When I edit a student I have a field (which is another custom taxonomy) called school.
I also have user profiles with the same school field in the edit screen.
Now… what I want to do is in my field group, have the student field but only populate it with student terms that have the same school term as the current post author.
e.g.
student term “Sally” has the school term “XYZ primary school”
student term “Billy” has the school term “ABC high school”
Therefore, the student term “Sally” would only populate the student field (in a post) when the current author also has the school term “XYZ primary school” in their user profile.
Does this make sense?
