It is permissible to share in the sacrifice, and a camel or a cow is sufficient for seven people
وَحَدَّثَنِي مُحَمَّدُ بْنُ حَاتِمٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنِ ابْنِ جُرَيْجٍ، أَخْبَرَنِي أَبُو الزُّبَيْرِ، أَنَّهُ سَمِعَ جَابِرَ بْنَ عَبْدِ اللَّهِ، قَالَ اشْتَرَكْنَا مَعَ النَّبِيِّ صلى الله عليه وسلم فِي الْحَجِّ وَالْعُمْرَةِ كُلُّ سَبْعَةٍ فِي بَدَنَةٍ فَقَالَ رَجُلٌ لِجَابِرٍ أَيُشْتَرَكُ فِي الْبَدَنَةِ مَا يُشْتَرَكُ فِي الْجَزُورِ قَالَ مَا هِيَ إِلاَّ مِنَ الْبُدْنِ . وَحَضَرَ جَابِرٌ الْحُدَيْبِيَةَ قَالَ نَحَرْنَا يَوْمَئِذٍ سَبْعِينَ بَدَنَةً اشْتَرَكْنَا كُلُّ سَبْعَةٍ فِي بَدَنَةٍ .
Jabir b. 'Abdullah (Allah be pleased with them) reported: We joined Allah's Messenger (may pea, @. e be upon him) in Hajj and Umra and seven persons shared in the sacrifice of an animal. A person said to Jabir (Allah be pleased with him): Can seven persons share in the sacrifice of al-Badnah (a camel) as he shares in al- Jazur (a cow)? He, (Jabir) said: It (al-Jazur) is nothing but one among the budun. Jabir was present at Hudaibiya and he said: We sacrificed on that day seventy camel, and seven men shared in each sacrifice (of camel).