And herein lies the basic error of the dispensational heresy, there is no longer TWO, there is only ONE people of God. The Church is NOT just a 'parenthesis', a 'glitch' in the scheme of things.
And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice: and they shall become one flock, one shepherd. Jn 10:16
having abolished in the flesh the enmity, even the law of commandments contained in ordinances; that he might create in himself of the two one new man, so making peace; Eph 2:15
For there is no distinction between Jew and Greek: for the same Lord is Lord of all, and is rich unto all that call upon him: Ro 10:12
where there cannot be Greek and Jew, circumcision and uncircumcision, barbarian, Scythian, bondman, freeman; but Christ is all, and in all. Col 3:11
There can be neither Jew nor Greek, there can be neither bond nor free, there can be no male and female; for ye all are one man in Christ Jesus. Gal 3:28
For in one Spirit were we all baptized into one body, whether Jews or Greeks, whether bond or free; and were all made to drink of one Spirit. 1 Cor 12:13
If/when the 'natural branches' are ever grafted back in, it will be to that which they were broken off from, and that is THE CHURCH OF CHRIST of the covenant of grace.