Is it permissible to perform the Maghrib prayer in congregation after the Isha’ prayer in congregation, or must it be performed individually, and is it necessary to repeat the Isha’ prayer?

It is permissible to perform the Maghrib prayer in congregation after performing the Isha prayer in congregation. The jurists have mentioned the obligation of sequencing between missed prayers and the current prayer, except when time is short. So, whoever forgets the sequencing and prays Isha before Maghrib is not obliged to repeat it. The Shafi'is are of the view that sequencing is not obligatory between missed prayers, nor between a missed prayer and a current prayer.