Not something we have built into the plugin at all, and I’m not aware of any ready-made plugins that handle this. Some searching around lead me to this snippet via https://circlecube.com/says/2013/01/set-default-terms-for-your-custom-taxonomy-default/:
<?php
/**
* Define default terms for custom taxonomies in WordPress 3.0.1
*
* @author Michael Fields https://wordpress.mfields.org/
* @props John P. Bloch https://www.johnpbloch.com/
* @props Evan Mulins https://circlecube.com/circlecube/
*
* @since 2010-09-13
* @alter 2013-01-31
*
* @license GPLv2
*/
function mfields_set_default_object_terms( $post_id, $post ) {
if ( 'publish' === $post->post_status && $post->post_type === 'your_custom_post_type' ) {
$defaults = array(
'your_taxonomy_id' => array( 'your_term_slug' )
);
$taxonomies = get_object_taxonomies( $post->post_type );
foreach ( (array) $taxonomies as $taxonomy ) {
$terms = wp_get_post_terms( $post_id, $taxonomy );
if ( empty( $terms ) && array_key_exists( $taxonomy, $defaults ) ) {
wp_set_object_terms( $post_id, $defaults[$taxonomy], $taxonomy );
}
}
}
}
add_action( 'save_post', 'mfields_set_default_object_terms', 100, 2 );
You would need to fill in the appropriate spots for the post type and taxonomy values. Since you’re dealing with 3, you may need to amend briefly to make it work for all at once. However, as a whole it should be possible. You’d want to save it to your theme’s functions.php or similar.
