I suppose you men a corrupted concept of what “members of One Body” means. What does “members of One Body” mean to you?
All true believers who rely on Christ alone by faith alone are members of the one body of Christ, part of the ekklesia. As we find in Revelation the membership in some local or regional organization is no assurance of membership of that ekklesia. The Lambs Book of Life has all the names of the saints of God recorded from Adam till the end of time. The word ekklesia in the New Testament never referred to some single "denomination" or organization with some structured hierarchy. In every instance it referred to a local meeting of those who put their trust in Jesus alone for their salvation. The ekklesia (those called out by God) have only one leader and that is Christ as their High Priest.