صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب ذكر أفعال اختلف الناس فى إباحته للمحرم، نصت سنة النبى صلى الله عليه وسلم أو دلت على إباحتهاChapters on Acts Permitted for the Pilgrim by Sunnah
(309) بَابُ إِبَاحَةِ اشْتِرَاكِ النَّفَرِ فِي الْبَدَنَةِ وَالْبَقَرَةِ الْوَاحِدَةِ،Chapter: Permissibility of sharing a camel or cow among several people
Hadith Q2900
وَإِنْ كَانَ مَنْ يَشْتَرِكُ فِي الْبَقَرَةِ الْوَاحِدَةِ أَوِ الْبَدَنَةِ الْوَاحِدَةِ مِنْ قَبَائِلَ شَتَّى لَيْسُوا مِنْ أَهْلِ بَيْتٍ وَاحِدٍ، مَعَ الدَّلِيلِ أَنَّ سُبْعَ بَدَنَةِ وَسُبْعَ بَقَرَةٍ تَقُومُ مَقَامَ شَاةٍ فِي الْهَدْيِ.
Even if those sharing are from different tribes and not from the same family. With the explanation that one-seventh share of a camel or a cow in sacrifice is equal to one goat.
