My question is about tahajjud in jamah when we go for camping programs. We wake up and pray together. But some are presently against it even when we prove that the companions on different occasions prayed with the companions non-obligatory prayers.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is permissible to offer supererogatory prayers in congregation according to the majority of scholars.

Ibn Qudama said in Al-Mughni: "It is permissible to offer supererogatory prayers individually or in congregation because the Prophet (Sallallahu Alaihi wa Sallam) did that both ways. However, most of his supererogatory prayers were performed individually. Once he prayed with Hudaifa, and once he prayed with Ibn Abbas, and one time he prayed with Anas and his mother, and an orphan. And once he led the prayer in the house of Ithban and the companions prayed behind him, and he led them in prayer as well during Ramadan three times."

Sheikh al Islam Ibn Taimiyyah said in Majmo'u Al fatawa 23/111: "The correct opinion is what is reported in the Sunnah, that it should not be disliked to perform supererogatory prayers in congregation as the Prophet (Sallallahu Alaihi wa Sallam) did so, and we should not make it as a proved Sunnah that should not be neglected like those who appoint an imam to pray these prayers between Magrib and Isha, or in the night continuously, in the same way that he leads them in the five obligatory prayers."

So if someone sometimes prays the night prayer, or unconditional supererogatory prayer in congregation, and does not perform it continuously, then it is acceptable.

As regards, the supererogatory prayers performed after or before obligatory prayers, or Istikharah prayer and a prayer that has a reason to be performed for, like the prayer after Wudu, the prayer of salutation to the mosque, and the like, then it is more appropriate to perform them individually.

Allah knows best.