All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Yes, it is permissible to hold another congregational prayer after the first congregation comes to an end.
Abu Sa'eed al-Khudri narrated that a man entered the mosque after the Prophet had finished the prayer with his Companions, and he said: “Whoever is ready to perform a prayer with this man and that will be a form of charity. Then, one of the present people prayed with the man in congregation.” [Ahmad, Abu Dawood and others]
Al-Albaani classified this Hadeeth as authentic. Al-Bukhari also reported that: “Anas came into a mosque where the prayer had been done. So, he called the Aathaan and the Iqaama and performed the prayer in congregation.” This is the opinion of Imam Ahmad, Ishaaq and some of the Companions and the Taabi’een (the generation that followed the companions), and it is the predominant opinion.
For more benefit on praying in congregation after the Imam has completed the prayer, please refer to Fatwa 83913.
Allah knows best.