Having a number of congregations for Taraweeh prayer in one mosque for the purpose of training those who have memorised the Qur’an in leading the prayer
Question

                Taraweeh prayers are held in congregation in the city of Old Delhi, with between four and five congregations in one mosque at the same time, because there are a lot of people who have memorised the Qur’an, and each one of them wants to lead the prayer. In fact in one mosque you will find four or five imams. Naturally the microphones are not given to any one of these congregations, so that no disturbance will be caused to the other congregations. How valid is that? What is the solution so that each of the people who have memorised the Qur’an can have a turn at leading the prayers?
Praise be to Allah.I put this question to our shaykh, ‘Abd ar-Rahmaan ibn Barraak (may Allah preserve him), and he replied that there is no  reason not to do that, so long as it serves a purpose and it will not cause a disturbance to some of them. 
In the beginning, the Sahaabah used to pray Taraweeh in more than one congregation, until ‘Umar united them in a single congregation. 
Al-Bukhaari (may Allah have mercy on him) narrated in his Saheeh (2010) from ‘Abd ar-Rahmaan ibn ‘Abd al-Qaari’ that he said: I went out with ‘Umar ibn al-Khattaab (may Allah be pleased with him) one night in Ramadan to the mosque, where we saw the people in scattered groups, one man praying by himself, and another man praying with a group of people following his prayer. ‘Umar said: I think that if I unite these people behind one reciter, it will be better. Then he decided to do that, so he united them behind Ubayy ibn Ka‘b. 
And Allah knows best.