What is the ruling on praying in congregation following the radio if it broadcasts the prayer of the capital directly, and is their prayer considered valid?

What these people do, praying behind the radio, is an incorrect and invalid act. This is due to the lack of connection between the rows. The one praying behind the radio prays behind an imam who is not in front of them, but rather separated by great distances. This leads to the invalidation of the congregational prayer or the Friday prayer. They are obligated to make up all the prayers they performed in this manner during the daytime, because they were neither valid nor sufficient to fulfill the obligation. The solution lies in one of them stepping forward to deliver the sermon and lead them in two rak'ahs.