It is narrated from Jabir (may Allah be pleased with him) who states: We performed sacrifices with the Prophet (ﷺ) at the place of Hudaybiyyah; a camel was sacrificed on behalf of seven people, and a cow was also sacrificed on behalf of seven people.
Hadith Referenceمسند الإمام الشافعي / كتاب العيدين والأضاحي والاستسقاء / 505
Hadith Takhrijاخرجه مسلم، الحج، باب جواز الاشتراك فى الهدى، واجزاء البدنه والبقرة .... الخ (1318)۔