I don't make the claim.
I just agree with the claim scripture makes.
Israel is elect and beloved of GOD even when they are enemies of the gospel.
This is a pertinent question . . .
The nation of Israel was
elect of God, because they were chosen out of all the nations, to temporarily represent the ordinances of God amongst all the heathen peoples. It was a sanctification (holy separation), but not necessarily salvation, for salvation comes by faith alone, and not all the nation of Israel understood or believed in their Godly role.
The believers in the covenant promises of a Seed and the life, death, and resurrection of Jesus Christ's fulfillment of those promises, were all
elect unto salvation, out of all unbelieving and sinful mankind, for they are gifted with supernatural faith in God's revelation of Christ's cross work on their behalf.
Jesus Christ is
Elect of God because He is the one and only Savior, born without sin, from all mankind.
"Election" is a doctrine that is poorly studied and understood. But bottom line, all it is, is a denial of Universalism/Nationalism; neither of which reveal the one, true Gospel message of God.
So when Calvinism claims that the elect are eternally saved, are there more than one group of 'elect' that GOD deals with differently than the other group of 'elect'?
No. The term "Elect" reveals and describes the sovereign actions and purposes of God, accomplished through His authority, wisdom, economy ("ways"), and will throughout history.