Dan ,Hi there.
Don't know quite what to say. My gransdfather, George or Jure (if I remember right) used the last name Plese. In the old country, Delnice and Crni Lug, Croatia, there was a small check mark over the s, giving it the sh sound so I changed it to spell Pleshe back in the 70s. I pretty much lost track of my dad's side of the family until a year or two ago when a fellow in Indiana emailed me and it turned out he was a second cousin.
I did go back to Delnice in 1975 and found, much top my surprise, many "Plese" grave stones. I did not feel, at that time to pursue it but it now seems possible that Luka and Jure were related but I have no evidence of that. Las I heard the Church of Latter Day Saints was recording and indexing the birth etc. records in Croatia but, I don't know.
If you would like to contact me directly, my address is firstname.lastname@example.org
(And I am now using Hummer as a frist name. Long story, for another time?
Peace and happy hunting!