Right.In the Church, there are no "other people". We are all priests.
Romans 15
(15) But on some points I have written to you very boldly by way of reminder, because of the grace given me by God
(16) to be a minister of Christ Jesus to the Gentiles in the priestly service of the gospel of God, so that the offering of the Gentiles may be acceptable, sanctified by the Holy Spirit.
But one does not have to attend a Catholic Mass to do the priestly service of the gospel of God.