Sahih Muslim 1318
Sahih Muslim · Book 15: The Book of Pilgrimage · It is permissible to share in the sacrifice, and a camel or a cow is sufficient for seven people
Jaibir b. 'Abdullah (Allah be pleased with them) reported:
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى ، أَخْبَرَنَا هُشَيْمٌ ، عَنْ عَبْدِ الْمَلِكِ ، عَنْ عَطَاءٍ ، عَنْ جَابِرِ بْنِ، عَبْدِ اللَّهِ قَالَ كُنَّا نَتَمَتَّعُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم بِالْعُمْرَةِ فَنَذْبَحُ الْبَقَرَةَ عَنْ سَبْعَةٍ نَشْتَرِكُ فِيهَا .
We performed Hajj Tamattu' along with Allah's Messenger (ﷺ) and we slaughtered a cow on behalf of seven persons sharing in it.