Ressler/Rössler 1888 Zrenjanin/Serbia

My grandfather ZSIGMOND RÖSSLER was born in Zrenjanin 1888. Zrenjanin is the present name of the city in Serbia. The Hungarian name was Nagybecskerek. His parents were MOR RESSLER and CECZILIA BERGENTHAL.
The name was spelled in different ways depending of the place where they lived:Resler, Rössler, Röszler. MOR RESSLER was a tailor. He died in Serbia, as well as his wife, probably around 1900, because my grandfather was send alone, very young, just a child, to his syster in Budapest. I don't have her name but I know she was married to ERNÖ DEIM. They lived in Budapest around 1919-21. I don't have any other information about them. My grandfather seems to had an other sister too BÖZSI (ERZSEBET?) RESSLER who also lived in Budapest, but I don't have any information about her either.

I wonder if somebody recognizes these names or has origins in Zrenjanin?

Susanna Vendel