Is it permissible to have multiple congregations in one mosque, especially when we are travelers?

Question:
A questioner says: We are young men who entered one of the mosques while traveling, and we missed the first congregation. We found a group praying, and their number was two. One of our young men said, "Do not pray with them; rather, pray on your own, for we are a congregation." We told him, "These people are a congregation, and it is not permissible for us to establish another congregation." He said, "These people do not display the signs of prayer, or the prayer is such and such," and he said, "We are more numerous than them and better." The question is: Is it permissible for us to join them, or should we pray on our own?

Answer:
It is not permissible to have multiple congregations in one mosque. So if you find a group praying, join them. Join them and follow the imam. Follow the imam. If he completes the prayer, you are required to complete it, even if you are travelers.
And if the imam is a traveler and you are residents, join him. When he says the closing salam, stand up and complete the prayer for yourselves, as the Prophet (peace and blessings be upon him) said: "O people of Makkah, we are a traveling people, so complete your prayer for yourselves." It is permissible for a traveler to pray behind a resident, but he must complete the prayer. It is permissible for a resident to pray behind a traveler. And when the traveler says the salam, the resident stands up and completes his prayer. As for having these people as one congregation and those people as another congregation in one place, that is division. We have been forbidden from division and disagreement, and we have been commanded to gather together.