No, the Church maintains that anyone who is validly baptized is a member of the Church, whether they separate themselves from communion or not.
The Church is one, and Christians participate in the Church fully (i.e. by being communicants of the Catholic Church) or defectively (being noncommunicant with the Catholic Church).
Jesus Christ ultimately judges who will gain heaven, and has mercy on whom He will.
The Catholic Church's position is that full membership in Christ's Church, i.e. the Catholic Church, is the only sure path to salvation - Christ may choose to save those who are separated from His Church, but don't count on it.
Just to second wideawake's response, there is a Catholic dogma (and thus infallible) that states: "Outside the Church there is no salvation."
But this dogma has never been taken to mean that only people *listed on the parish rolls* will go to heaven. There is a canonized saint, St. Emerentiana, who was never actually baptized...she died a catechumen and was never received into the Church formally. Yet we know beyond all doubt that she is in heaven.
Anyway, with a very few exceptions (JW's, Mormons, etc), Protestant baptisms are recognized as valid by the Catholic Church. That means that every Protestant is *actually* a baptized member of the (Catholic) Church, whether he or she knows it, admits it, or not.
Now that doesn't mean Protestants automatically go to heaven--we don't believe in once saved always saved. And we have to admit that it is much much *harder* for Protestants to get to heaven because those denominations lack the sacraments that Christ instituted to help us get to heaven (no Confession, no Communion).
So a personal in a denomination (or even a perfect pagan) CAN be saved...but IF they are, that only happens because somehow, someway, unknown perhaps to anyone on this earth, they were invisibly united to the visible Catholic Church.
I hope that makes sense...it's a confusing issue even to Catholics.
You are SOOOOO wrong. How arrogant you folks have become, thinking your church is the ONLY church. You will be shocked to see us protestants in the same line as your are in heaven. Cheez.