Dear 22 guerra
You will NOT find info in Austria for SESTRIC(H). They came from Croatia, which at that time was under the rule of the Austro-Hungarian Empire. Specifically the part of Croatia where they are from was under the rule of the Hungary part of the Empire. BUT all records will be found in Croatia.
There are records for several men named Michael or Mike SESTRICH found in KC, approximate birth years are 1868, 1895, 1890 and 1924.... which one is your Great Grandfather? What was his wife's name?
The SESTRIC (Croatian spelling) I have helped research come from near Ribnik, Croatia. If you can give more info maybe I can lead you in the right direction. I took my Heritage Group Tour last year to that area and will be there again Sept 2013.
Croatian Heritage Museum