Is one sacrifice sufficient for a husband, his wife, and their eight children, and is it permissible to share one sacrifice with a neighbor if a single one is sufficient?

A single sheep offered as a sacrifice (Uḍḥiyah) is sufficient for a man, his household, and any Muslims he wishes to include. The Prophet, peace and blessings be upon him, sacrificed a ram on behalf of himself and his Ummah. During his time, a man would sacrifice a sheep on behalf of himself and his household. A seventh of a camel or a seventh of a cow is sufficient for what a single sheep would suffice for. However, a single sheep is not sufficient for two or more people who share in it, nor is it permissible for eight or more people to share in a camel or a cow, because acts of worship are prescriptive (tawqifiyyah).