بسم الله الرحمن الرحيم
(Fatwa: 40/48/D=1/1438)
It is makrooh to establish second jamat in the mosque whether jamat of any of the five times of salah or Jumuah salah, it is necessary to avoid. As per the situation mentioned in the question. The Masjid Committee should expand the mosque or they should build new mosque. If it is not possible, then the second jamat should be arranged somewhere else instead of the mosque such as in a big hall, ground, vacant place of the maktab or factory etc. If such options are available then it is not allowed to establish second and third Jumuah jamat in the mosque.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband
