Hi - I don't think the two families are closely related. The Iowa one went directly to Iowa, and didn't stop in the Pittsburgh area.
You might get some help with their home-town if you can find an obituary. Some of the old obituaries are full of history.
I also checked my photocopies from Baca's "Czech Immigration Passenger Lists", however, I didn't see a family that sounded like yours. (Vencil or Wenzel was fairly common for Hrabak men.)