I believe Hintehajt is actually Hinterhaid in Czech. now known as Zadni Bor.
This village is one of about 48 villages that was incorporated into the military training grounds of Boletice in 1950 and thus no longer exists.
LDS has a 1921 census for the area:
It can be accessed digitally here - perhaps you'll find some cousins there:https://familysearch.org/pal:/MM9.3.1/TH-1971-36231-1357-3?c...
It definitely has Gruber families listed in the census.
These church records were a part of the parish of Andreasburg - here are the specifics:http://www.genealogienetz.de/reg/SUD/kb/andreasberg.html