Tell us what you are trying to do?
I have 3 custom fields, A, B and C. 2 relationships many to many, C to A and C to B. Each relationship has a custom field , K. I want to add a dropdown filter a view that shows posts with custom fields A and B, so user can filter the results. I want that filter to only show options that include Cs that are in a relation with either A or B AND they have K to be true.
Is there any documentation that you are following?
no
However - reading your requirement there is no such option available to filter the custom search result as per your requirement.
If you can share problem URL and admin access details and tell me with what options what is your expected results and setup a test site I will try to reivew and check if I've any workaround to share.
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin and FTP) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.