Load does not work for dynamical relationships?

Imagine you have the following two relations: /** * Relation working/holiday/.. hours * @return [type] [description] */ public function relatedHours($type = null) { $type = $type ?? $this->type; return $this->hours()->where(‘type’, ‘=’, $type); } public function workingHours() { return $this->relatedHours(Type::WORK); }