Wanted to say thanks so much for this thread. Swiss Fraser, I am in the midst of exactly the same process you state for your reason. I am separating out my line from my husbands line in order to upload and blog each line seperately to their own external websites. I thought I'd be hours individually deleting about 1,300 individuals from each new tree.
Y'all saved me a BIG headache by posting this question. And A tremendous thanks to silverfox for the answer.