Restrict acf-json Sync for Specific Field Groups in Advanced Custom Fields

<?php
/**
 * prevent acf-json sync on specific fields 
 *
 */
add_filter('acf/get_field_group', 'wd_restrict_json_sync_field_groups', 20);
function wd_restrict_json_sync_field_groups($group) {

	if ( $group['key'] == 'INSERT FIELD GROUP ID' ) {
		$group['private'] = 1;
	}
	return $group;
}