It's Not Over! Kyle Richards & Kathy Hilton Go To New Low In Nasty Feud

Kyle Richards can't let her family feud end! In the latest round, RadarOnline.com has exclusively learned she has even accused her older sister of being a shameless social climber.

The Real Housewives of Beverly Hills star is estranged from both of her sisters and despite a picture she shared with Kathy Hilton over the holidays, their relationship is far from friendly.

"There is no truce between Kyle and Kathy," a source close to the situation told RadarOnline.com, despite the cozy snapshot taken at Kris Jenner's Christmas party.

"That photo was a total set up," the source said. "They're not getting along at all right now because their family issues go much deeper than they will ever reveal on a reality show."

Unbelievably, Nicky Hilton's summer 2015 wedding at Kensington Palace is still a sore point for the siblings.

"Chelsea Clinton was invited to the wedding but Kyle's two kids Alexia and Sophia were not. That stung Kyle," the source told RadarOnline.com.

"The Hiltons don't even know the Clintons so it is even more hurtful. And then Kathy and Nicky come up with the excuse that the Rothschilds know them well? That's a ridiculous story that Kyle just couldn't believe!" the source scoffed. "It was the lowest of insults. It makes Kyle think that Kathy is really becoming a social climber."

Now, as their problems are playing out on RHOBH, the source told RadarOnline.com that Richards is truly stunned by her sister.