It was a full court of Kennedys — 35, to be exact — at HBO’s Oct. 15 screening of “Ethel,” Rory Kennedy’s docu tribute to her mother, Ethel.“I’ve seen it a hundred times, and I can’t watch it without tears,” HBO’s Sheila Nevins said at the Time Warner Center. “There are many levels of this: the mother-daughter aspect, which is very poignant, and this incredible history, shared by one more than the other because Ethel was pregnant with Rory when Robert Kennedy was shot. “I always wanted to do this film,” Nevins said. “I never thought it would happen.” Rory said the film chronicles a family life that just happened to be lived on the front lines of history. “What was it like for my mother having 11 children and 19 dogs and horses and zebras and a seal?” she notes. “It’s really documenting, pulling out archival footage that has never been seen before. Hopefully there’s a lot there even for people who are familiar with our family. Even some historians have said they’ve gotten new information from this.” So what does Ethel Kennedy herself think of the docu? She quickly pivoted to talk about her late husband’s fight for equality and tolerance. “That was very much what Bobby stood for and what the children learned at the dinner table and carried on in their own lives,” Ethel said. “It’s really great to see it continue to happen. Look at Rory’s life and,” she said, eager to change the subject, “her next documentary is going to be really spectacular.” Rory smiled, saying, “She’s just happy it’s not going to be ‘Ethel 2.’ ” Actually, her next docu is on the end of the Vietnam war.