After several phone calls to cemeteries around New York City, I located the relatives listed below at:
Hungarian Union Fields
83-45 Cypress Hills Street
Ridgewood, NY 11385
The information on graves is maintained by Mt. Carmel Cemetery (718-366-5900)
Simon and Sofia Zweighaft, our great grandparents
Bernard and Blanche Zweighaft, our paternal grandparents
Adolph and Helena Zweighaft Hirschberg, our grand uncle and aunt (Helena is the sister of Bernard)
Seymour and Jane Hirschberg London (Jane is the child of Adolph and Helena)
Leo and Jolan Hirschberg (Leo is the child of Adolph and Helena)
I was hoping to visit the cemetery on the way back from upstate New York, but as it was a Friday afternoon in the summer and the traffic was likely going to be horrific, plans were made instead to return sometime later this summer or fall with mauseleum key in hand. Mary and I will make the trip together and would welcome other brave souls who dare to venture into a mauseleum probably unopened for at least 50 years.
Here is a copy of the letter from the cemetery in 1994, sent while I was corresponding with Leo's 2nd wife, Alva.