It is permissible to share in the sacrifice, and a camel or a cow is sufficient for seven people
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا مَالِكٌ، ح وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، - وَاللَّفْظُ لَهُ - قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ أَبِي الزُّبَيْرِ عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ قَالَ نَحَرْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم عَامَ الْحُدَيْبِيَةِ الْبَدَنَةَ عَنْ سَبْعَةٍ وَالْبَقَرَةَ عَنْ سَبْعَةٍ .
Jabir b. 'Abdullah (Allah be pleased with him) reported: In the year of Hudaibiya (6 H ), we, along with Allah's Messenger (way peace be upon him), sacrificed a camel for seven persons and a cow for seven persons.