Is it Islamically permissible to perform the Friday prayer in a small prayer room at work for four people, knowing that there is no other alternative for them?

If the Friday prayer is established in the city, you are obligated to pray with the congregation, and it is not permissible to hold another Friday prayer. If it is not established in the city, it becomes obligatory to establish it, and it is not permissible to pray Dhuhr instead, because establishing it is an obligation upon Muslims. Its validity requires a congregation, without stipulating a specific number. It is valid with three or more, and it is not permissible to pray Dhuhr instead due to a shortage in number, because Allah Almighty says: "then hasten to the remembrance of Allah."