Is one Udhiyah sufficient for two wives living in two separate houses, or are two Udhiyahs required?

A single sacrifice (udhiyah) is sufficient for you and all the members of your household, even if they are numerous. The Prophet, peace and blessings be upon him, sacrificed a single sheep for himself and his family, and it was not reported that he commanded each of his wives to offer a separate sacrifice. This was also the practice of the Companion Abu Ayyub al-Ansari, and during the time of the Messenger of Allah, peace and blessings be upon him, a man would sacrifice a sheep for himself and his household. The Companion Abdullah ibn Hisham also used to offer a single sheep as a sacrifice for his entire family. Therefore, one sacrifice is sufficient for two or more households as long as the owner is the same. However, it is preferable for each household to offer an independent sacrifice.