How should the latecomer complete their prayer when joining a group praying in separate segments (as in the situation where the Imam divided the congregation)?
General Chapter
Al-Mughni
Book of the Prayer of Fear
Primary text
If the Imam divided the congregation such that the first group prays one Rak'ah with him, and the second group prays two Rak'ahs, the second group completes one more Rak'ah, reciting Al-Fatiha only, while the first group completes two more Rak'ahs reciting Al-Fatiha and a Surah in each. This view is held by Malik, Al-Awza'i, Sufyan, and one position of Al-Shafi'i.
Supporting text
Another opinion of Al-Shafi'i states the first group should pray two Rak'ahs, and the second group one, based on tradition ascribed to 'Ali (may Allah be pleased with him) regarding the night of Hadir. This reasoning suggests the first group, having achieved the merit of the opening Takbir and leading, should be given precedence in the remaining portion, while the second group's completion of their part (catching the second segment) offsets their deficit. The sound position is that if differentiation is unavoidable, the first group is more deserving of precedence, and the second group's joining at the Imam's concluding part covers what they missed in sequence.