My parents live overseas, and my in-laws live in LA. They haven't really spent much time together since Bee and I got married 10 years ago! A few years ago though, Bee's mom came with us to my parents' place during our annual summer trip and they got to interact for two weeks or so.

Other than that, they don't really communicate with each other - probably because my parents are 12 time zones away, and international phone calls sound like you're calling a war zone.

I do think they'd enjoy spending time together though! Maybe one day we can make that happen.