He has two wives; should he offer two sacrifices?
Question

I have two wives, each of whom lives in her own house. Is it sufficient for me to offer one sacrifice or do I have to offer two?.
Praise be to Allah.It is sufficient for you to offer one sacrifice. In the answer to question no. (45916) we stated that one sacrifice is sufficient for a man and the members of his family even if they are one hundred strong, and the Prophet (peace and blessings of Allaah be upon him) used to offer a single sheep on behalf of himself and his family, and when he (peace and blessings of Allaah be upon him) died he left behind nine wives. 
Al-Qurtubi said: 
There is no report that the Prophet (peace and blessings of Allaah be upon him) ordered each of his wives to offer a separate sacrifice, even though the sacrifice was repeated every year and his wives were numerous. This would have been narrated if it has happened, as other minor issues were narrated. This is supported by the report narrated by Maalik, Ibn Maajah and al-Tirmidhi, who classed it as saheeh via ‘Ata’ ibn Yasaar: I asked Abu Ayyoob: How was the sacrifice done at the time of the Messenger of Allaah (peace and blessings of Allaah be upon him)? He said: A man would offer a sheep on behalf of himself and the members of his family, and they would eat some and feed others with some.” End quote from Fath al-Baari. The hadeeth was classed as saheeh by al-Albaani in Saheeh al-Tirmidhi. 
Al-Bukhaari (7210) narrated from ‘Abd-Allaah ibn Hishaam (may Allaah be pleased with him), that he met the Prophet (peace and blessings of Allaah be upon him) when his mother Zaynab bint Humayd took him to the Messenger of Allaah (peace and blessings of Allaah be upon him), and said: “O Messenger of Allaah, accept his oath of allegiance.” The Prophet (peace and blessings of Allaah be upon him) said, “He is too young.” He patted him on the head and made du’aa’ for him, and he used to sacrifice a single sheep on behalf of his whole family. 
Al-Haafiz said: The phrase “and he used to sacrifice a single sheep on behalf of his whole family” refers to ‘Abd-Allaah ibn Hishaam. End quote. 
The Standing Committee was asked: 
I have two households which are about fifteen kilometers apart, and I want to offer the sacrifice. Should I offer a sacrifice at each house, or at one house? 
They replied: 
It is sufficient for you to offer one sacrifice on behalf of your two households, so long as the head of both is one person. But if you offer a separate sacrifice at each house, that is better. End quote. 
Fataawa al-Lajnah al-Daa’imah, 11/407.