I would not join such a group as it includes people from groups that believe and teach things that are counter to Scripture. I am not talking about minor issues but essential doctrines related to the person and work of Christ. These are essential because they are salvation issues.
They are gospel salvation issues. not eternal salvation issues. one believes Christ is both God and man because he is first of all, regenerate, and one is regenerate not by any human action but by the action of the Spirit, and the Spirit regenerates only those that are His, and those that are His are those whose names He wrote down in the Lamb's Book of Life, and those names were written from the foundation of the world, and when those names were known of God and put in His mind (the Book) the denomination, doctrines, creed, or lack of these were not in consideration. The only consideration was mercy, His Sovereign right to be merciful to whom He will.
He redeemed them based on His will, not their act. That salvation was eternal, solely and purely by grace.
Now, when these in this plane we call time, whom He redeemed unto Himself for purposes of being with Him in eternity, are brought under gospel instruction, or catechetical instruction, or doctrinal instruction (choose which one you want to call it), they will convert to whichever instruction gets to them first, and they become members of that denomination that they get to first, or first gets to them, or which they join for whatever reason, and when they do, IF their names are known of God, their ETERNAL destination is unchanged.
If these children of God, whom He chose unto Himself from eternity past, happen to be born in a country with a different creed, growing up under that creed, then they will go through this plane called time, subjects to and of that creed, but their ETERNITY is unchanged.
They belong to Christ, because Christ purchased them with His blood, not because they were worthy to be redeemed, but because it is the Father's will, and Christ carried out His Father's will for them.
That is grace, unadulterated, from Heaven, based purely on the mercy and character of God.
If our eternal salvation were based on our doctrines, we are of all men, confused and as damnable as the wicked in God's sight.