"Where two or three are gather in my name, there I am in the midst". When someone is "disfellowshiped" from the Church, they are ostensibly disfellowshipped from God. That is the "correlation" between the invisible God and His visible Church.The Romans 11 statement appears to be about "Standing by faith" where individuals in the Jewish group stand and some fall - and individuals in the Gentile group stand while others never even join to start with.
The warning appears to be about perseverance (just as we see in Romans 2:6-7) - and it is individual.
The "invisible" body of Christ - means that this text applies to every saint world wide - no matter what location or denomination or circumstance they may be in. There is nothing mentioned in Romans 11 about "disfellowshiping" unbelieving Jews - it is not an act of "an organization" but the act of God in "not sparing them". Non-believing Jews were not applying to Jewish Christians "for membership" or for "questions discipline questions".
Thus from that perspective -- it has to be the invisible church.
in Christ,
Bob