[biblewonk]

That is the definition of taking a group of persons from within the community of priests and assigning them particular functions, yes. The sufferings from service can be offered up as a spiritual sacrifice, which is a particular priestly function. Leading the community in prayer is leading a sacrifice of prayer, a spiritual sacrifice proper to the priestly people. Again, this is what the presbyter's role is at Mass (when he is celebrating): to preside over the sacrifice of praise and thanksgiving, to lead many of the prayers, and to play the role of Christ in the re-presentation of the Lord's Supper.

If everyone called everyone priest that you might have something like this. But this is not the case. Your priests are professionals and do most of the ministering. They are the only ones known as priests and they are probably the only ones that are allowed to perform your various sacrements. I think there are seven sacrements and there may be cases where a non priest can perform them.

[annalex]

I think there are seven sacrements and there may be cases where a non priest can perform them.

Baptism, Confession, Eucharist, Confirmation, Marriage, Holy Orders, Extreme Unction.

Seven Sacraments

A layman, even a non-Christian can perform Baptism as an emergency when the baptised is about to die. The valid trinitarian formula must be used, as well as, of course, water, and the celebrant must intend that to be Christian baptism. I am not aware of other exceptions.