Is it permissible to visit relatives who live far from the mosque, making it difficult to perform congregational prayers, or should the visit be cut short to preserve congregational prayer?

Congregational prayer is obligatory for an able-bodied man if he hears the call. Hearing the call means hearing the adhan (call to prayer) with a normal voice, without amplification, provided the mu'adhin (caller to prayer) raises his voice and there is no wind. If you do not hear the call due to distance, you are excused from attending congregational prayer, and there is no sin upon you. You may visit your relatives and pray in congregation at home. If you are excused, you will receive the full reward of congregational prayer, based on the Prophet's (peace be upon him) saying: "Deeds are but by intentions," and the hadith narrated by Anas (may Allah be pleased with him) that the Prophet (peace be upon him) said: "Indeed, in Medina are people who, whenever you traveled a distance or crossed a valley, they were with you, being detained by an excuse."