I have previously commended the excellent book Concerning the True Care of Souls, by Martin Bucer. In his discussion of Titus 1:5-7 Bucer argues the text (and others like it) require a plurality of elders and that these elders are to be pastors engaged in the oversight of souls (not a corporate board as is too often the case today). No one serves as a pastor/elder/bishop/overseer unless he is engaged in the care of souls.
“From this it can be clearly seen that the apostle here means elders who will be bishops, that is, the proper overseers, carers of souls, and shepherds of the flock of Christ. That is why it is the Holy Spiritâ€™s rule that each church should have several elders, who are all shepherds and bishops, that is, overseers to carry out the care of souls and the pastoral office.â€ (35-36).