Hi Lorenza,
If my calculations are correct, you and I are sixth cousins. I have a few Martellos in my family tree but do not have Sisto. Is he related on the Isabella side?
I also do not have any siblings or descendants of Concetta Bucci in my tree. Would you be willing to share your tree.
My email is
walsh.tomj@gmail.com if you would like to contact me.
Thanks!
-Tom