That at least is clear. While the New Testament is not so clear on the point as some seem to think, there is surely a common-sense point of view. It would appear a wise thing to appoint elders over groups of smaller churches or districts as probably obtained at Ephesus where it seems unlikely that elders were appointed for every little house group. Again we must exercise commonsense and use some measure of interpretation. This work on the face of it has no reference to a congregation or group, but it does not follow that there was no such reference to the congregation by Titus.
Nothing however is proven.
In Acts 1 an appointment was made of a successor to Judas in the following manner. Peter urged that there should be the appointment. They assembled one hundred and twenty put forward two and after prayer, the names were submitted, not to a ballot according to modern practice, but to lot, which latter seems to us a strange way to settle the matter. Afterward they were set before the apostles who prayed and laid their hands upon them. Those 5000 quite obviously did not meet for church services in one building.