Shared Flashback

Some time around That 70’s Show, maybe earlier, but certainly post-Seinfeld, characters in sitcoms gained the ability to have a shared flashback to instantly and graphically communicate with one another.

What’s really odd is that they often know they can do this, and even make meta-jokes about this phenomenon.

Is there a word for this? It seems to me to be something unique to the television storytelling medium, and fairly recent, and we all seem to Just Get It.