"Remember, Paul wrote a letter to the Romans and he didn’t even know them."
... then perhaps you can explain Chapter 16 of Romans...?
3 Greet Prisca and Aquila, my fellow workers in Christ Jesus,
4 who for my life risked their own necks, to whom not only do I give thanks, but also all the churches of the Gentiles;
5 also greet the church that is in their house. Greet Epaenetus, my beloved, who is the first convert to Christ from Asia.
6 Greet Mary, who has worked hard for you.
7 Greet Andronicus and Junias, my kinsmen and my fellow prisoners, who are outstanding among the apostles, who also were in Christ before me.
8 Greet Ampliatus, my beloved in the Lord.
9 Greet Urbanus, our fellow worker in Christ, and Stachys my beloved.
10 Greet Apelles, the approved in Christ. Greet those who are of the household of Aristobulus.
11 Greet Herodion, my kinsman. Greet those of the household of Narcissus, who are in the Lord.
12 Greet Tryphaena and Tryphosa, workers in the Lord. Greet Persis the beloved, who has worked hard in the Lord.
13 Greet Rufus, a choice man in the Lord, also his mother and mine.
14 Greet Asyncritus, Phlegon, Hermes, Patrobas, Hermas and the brethren with them.
15 Greet Philologus and Julia, Nereus and his sister, and Olympas, and all the saints who are with them.