In the case of the book of Colossians, Paul near the beginning says how he teaches with all wisdom but near the middle says you (plural) teach each other in all wisdom, so in some sense the whole church teaches each other. That said, I think there is an increase in intensity of teaching, pastor being a shepherd term, elders , BTW typically in the plural in the NT, also being shepherds and how can you shepherd apart from the word. I believe the word pastor only appears once in the New Testament, shepherd many times Clearly there is a gift of teaching, but there's a gift of mercy and everyone needs to be merciful but some are especially so. Everyone in the church is an object lesson of truth one way or another. Some prolific talented commentators, like Gene Getz in measure of a man, say an elder may be teachable and not a teacher, but it's probably more true to say an elder should be both teachable and a teacher in my opinion.
The term translated pastors appears once in the New Testament. ESV translates it as shepherds. There is an issue whether the phrase is pastor and teachers meant to mean a special group who is both shepherds and teachers and some just shepherds but I don't see how you can shepherd apart form the word of God which makes one a type of a teacher.
Ephesians 4:11English Standard Version Anglicised (ESVUK) 11 And he gave the apostles, the prophets, the evangelists, the shepherds and teachers,
Ephesians 4:11 So Christ himself gave the apostles, the prophets, the evangelists, the pastors and teachers, NIV
Ephesians 4:11Common English Bible (CEB) 11 He gave some apostles, some prophets, some evangelists, and some pastors and teachers.
Elders appears many many times in the NT in contrast to the word sometimes translated Pastor appearing once.
In the PCA all elders are given titles elder, pastor, teacher, bishop and presbyter in the BOC on the elder (office of elder in the singular precluding only giving those titles to special elders) .... he [the elder, any elder] expounds the Word, and by sound doctrine both exhorts and convinces the gainsayer, he is termed teacher... They should instruct the ignorant, ....
PCA articulation
BOC The elder
8-1. This office is one of dignity and usefulness. The man who fills it has in Scripture different titles expressive of his various duties. As he has the oversight of the flock of Christ, he is termed bishop or pastor. As it is his duty to be grave and prudent, an example to the flock, and to govern well in the house and Kingdom of Christ, he is termed presbyter or elder. As he expounds the Word, and by sound doctrine both exhorts and convinces the gainsayer, he is termed teacher. These titles do not indicate different grades of office, but all describe one and the same office.
http://www.valleypresbyterian.org/elders/boco_chapters_1-20.htm#CHAPTER 8
then some discussion of Teaching elders as a specially gifted and normative preaching group and circling back to ruling elders
I think in the PCA a teaching elder is the only one authorized to serve communion or give a benediction, blessing, a pastor of word and sacrement
8-9. Elders being of one class of office, ruling elders possess the same authority and eligibility to office in the courts of the church as teaching elders. They [the ruling elders] should, moreover, cultivate zealously their own aptness to teach the Bible and should improve every opportunity of doing so.