Force term from a mandatory list

Hi,

I am wondering if your plugin can support, or already supports the ability to have a list of “Mandatory” terms. Alternatively a WP filter where I could add “Mandatory” terms.

For example

A site has 100k+ tags, in those tags resides ‘news’, ‘opinion’, ‘article’.
I would like to force the required taxonomy(this example post_tag) to always include one of these mandatory, regardless of any other tag selected.

This would require either;
A) an extra field for each taxonomy that’s selected as “required”. Within that field would have to be a search-based multiselect that leverages Ajax, some sites I work on have over 100k+ tags.
B) A WP Filter, where you can filter the “Mandatory” terms programmatically.

Thanks

Anthony