Hbr 7:15 And it is yet far more evident: for that after the similitude of Melchisedec there ariseth another priest
This is really sad.. my friend.. This is talking about Christ. a PRIEST..not priests.. Hebrews is about Christ
The OT priesthood was a TYPE of Christ ..offering a sacrifice for sin.. The priesthood type was fulfilled at the cross ... God put an exclamation mark on the destruction of the type when he destroyed the jewish priesthood in 70 ad
God clearly outlines the roles in the new church in the NT and there is no priesthood
The priesthood was established by Christ at the Last Supper when He commanded the apostles to "Do this in Commemoration of Me." Yet your scriptural challenged interpretation can't fathom the words of out Savior. In the end maybe your group lacks competence and must remain in this perpetual state of blissful ignorance but continue to pray to the Spirit for wisdom. God bless.