So, if I am following correctly, Titus Goldstein's (b abt 1862-1865) father was Joseph Goldstein and Leah Blum. Chaya Rivka Goldstein's (b abt 1856) father was Joseph Goldstein and Riva (?) Blum. Titus and his family left Iasi in 1899-1901. Chaya and her family left Iasi at various times between 1901 - 1920.
I think now there is a good chance that Titus and Chaya may have been siblings. Let's do a little more research on this. I'll message you.