FacetWP – create meta-choices

<?php

// Add to your (child) theme's functions.php and re-index afterwards!

add_filter( 'facetwp_index_row', function( $params, $class ) {
	if ( 'recognition' == $params['facet_name'] ) {
		$new_params = $params;
		$label = $params['facet_display_value'];

		if ( false !== strpos( $label, 'National Winner' ) ) {
			$new_params['facet_value'] = 'national-winners';
			$new_params['facet_display_value'] = 'All National Winners';
			$class->insert( $new_params );

			$new_params['facet_value'] = 'all-winners';
			$new_params['facet_display_value'] = 'All Winners';
			$class->insert( $new_params );
		}

		if ( false !== strpos( $label, 'Place in School' ) ) {
			$new_params['facet_value'] = 'all-winners';
			$new_params['facet_display_value'] = 'All Winners';
			$class->insert( $new_params );
		}
	}

	return $params;
}, 10, 2 );