We belong to the Catholic Church; I happen to attend the Roman Rite. If I decided to attend the Russian Orthodox Church starting today, then that is fine and good within the Church.
We have the same doctrine, beliefs, Mass, and Sacraments. Only the drapes are a different colour.
The true church may include your church(es), but the Body of Christ is the one and only true church. I know we will never agree on that, Mark.