Khloe Kardashian said she was left "frustrated" by sister Kourtney's reluctance to share her private life on the family's reality TV show.
finished last week after 14 years and 20 seasons.
It made stars of the sisters, who frequently allowed the cameras to capture some of the most stressful moments of their lives.
The cheating scandal involving Khloe's partner Tristan Thompson featured in later seasons of the show, while Kourtney's relationship with former boyfriend Scott Disick was also a regular fixture.
However, Kourtney is said to have barred the sisters from addressing her new relationship with rock star Travis Barker.
In a teaser for a reunion special hosted by US TV personality Andy Cohen, Khloe, 36, was asked if she felt she had "carried"in its later years.
She said: "I mean there's been times that I think maybe what I was going through, because you could also say Kourtney and Scott at the beginning, so much was about them. But maybe there wasn't as much going on in other people's lives.
"If other people are going through things and they're choosing not to share that's when it's unfair, but if there's really nothing else going on in someone's life what are they supposed to share?"
Asked by Cohen if there was a specific example of someone not sharing on screen, Khloe said Kourtney, 42, refused to include discussions about Barker, 45.
She said: "Well, like Kourt, I think Kourt learned from how much the public was in her relationship with Scott, it made her not want to share future dating relationships.
- The first of two reunion special episodes of will be available on the Hayu channel on Friday.