'ingredient_name', 'Amount' => 'get_count()' ); protected $single_router_name = 'admin:ing-cat-rel'; protected $verbose_name = "ingredients in recipe"; protected $verbose_name_multiply = "ingredients in recipe"; public function custom_filter_fields() { $recipe_id = $this->url_context['url_1']; return array( [ 'name' => 'obj.recipe_id', 'type' => '=', 'value' => $recipe_id ] ); } }