My great grandmother, Helen ROPP had 2 half siblings.
Irene and Frank ROPP were the children of Ernest J. ROPP (Helens father) and Mary. I was told by a distant relative that Mary's last name was Holleran, though I don't have any documented proof of that myself.
Recently a few of us ROPP "cousins" started emailing one another with information we knew and one day, one of these gentleman share this link with us:
Since my focus to this point has been on my immediate family, I don't have any information about Irene or Frank, but it seems from this post that the two of them spent some time in an orphange, which makes me wonder if perhaps Helen was there as well. In recent exchanges with one of Helen's daughters I got the impression Helen and her half siblings were not very close, despite all living in the MA area.
If anyone knows more about the orphanage being refered to in the post above, please take a moment to share with us through a comment here and/or by posting an answer to the original query.