Haha...the fold was Israel...the other sheep are gentiles.
Like I said earlier..."foundational".
Look at it this way, in Biblical times there were millions of people living in continents all around the world that were completely unknown to the disciples and the rest of the Biblical civilizations. The existence of these other children of G-d in no way takes away from the importance of the Biblical children of G-d.
Why is it so difficult to believe that there are other children of G-d living on planets currently unknown to us? Perhaps we are destined to someday bring them the Word. Perhaps they already have received the Word. Most likely there are civilizations so distant that we can never know of their existence and they can never know of ours.
Like I said above, its an awfully big universe.