This idea is that the Jewish and Gentile church are somehow distinct. This idea is to be rejected outright on the basis of Ephesians 2:15.
Ultimately, this is tantamount to racism. Yes, God has a plan for the Jewish people. Yes, He will save the whole nation at some point (Ezekiel 39). But, the church is never to be divided, as a house divided against itself cannot stand (Mark 3:24, John 17:11).
There is to be no distinction between Jew and Gentile, even as Paul rebuked Peter for no longer sitting and eating with the Gentiles in Galatians 2.
What God has joined together, let no man separate!