Enforcement Rules for State Compensation Law Article 15

Where there are several liable compensating authorities involved in the same legal relation, the liable compensating authority being requested shall send a written notification to request other liable authorities to participate in the negotiation. If other liable authorities do not participate in the negotiation, the liable compensating authority being requested shall notify other authorities the result of the negotiation accordingly.
中文原文 國家賠償法施行細則第15條
同一賠償事件,數機關均應負損害賠償責任時,被請求之賠償義務機關,應以書面通知未被請求之賠償義務機關參加協議。
未被請求之賠償義務機關未參加協議者,被請求之賠償義務機關,應將協議結果通知之,以為處理之依據。

English translation for reference only; the Chinese text prevails. Not legal advice.