I don't see Ephesians 1:1 as distinguishing between two groups ("saints" and "faithful in Christ Jesus." I agree with what Jamieson, Fausset and Brown wrote in their commentary: "to the saints ... and to the faithful — The same persons are referred to by both designations, as the Greek proves: “to those who are saints, and faithful in Christ Jesus.” The sanctification by God is here put before man’s faith. The twofold aspect of salvation is thus presented, God’s grace in the first instance sanctifying us, (that is, setting us apart in His eternal purposes as holy unto Himself); and our faith, by God’s gift, laying hold of salvation (2Th_2:13; 1Pe_1:2)."