The only predetermined group is the 144,000 out of the 12 tribes of Israel.
And I heard the number of those who were sealed. One hundred and forty-four thousand of all the tribes of the children of Israel were sealed:
of the tribe of Judah twelve thousand were sealed;
of the tribe of Reuben twelve thousand were sealed;
of the tribe of Gad twelve thousand were sealed;
of the tribe of Asher twelve thousand were sealed;
of the tribe of Naphtali twelve thousand were sealed;
of the tribe of Manasseh twelve thousand were sealed;
of the tribe of Simeon twelve thousand were sealed;
of the tribe of Levi twelve thousand were sealed;
of the tribe of Issachar twelve thousand were sealed;
of the tribe of Zebulun twelve thousand were sealed;
of the tribe of Joseph twelve thousand were sealed;
of the tribe of Benjamin twelve thousand were sealed.
After these things I looked, and behold, a great multitude which no one could number, of all nations, tribes, peoples, and tongues, standing before the throne and before the Lamb, clothed with white robes, with palm branches in their hands, and crying out with a loud voice, saying, “Salvation belongs to our God who sits on the throne, and to the Lamb!”
Revelation 7:4-10
In addition to the 144,000 from the tribes of Israel,
there is a great multitude that no one can number, who are in heaven, standing before the throne of God and the Lamb.
Maybe you should re-think your perspective.