Ideas which Christmas movie I am looking for?

Hey!

I’ve been searching for years this Christmas movie. This post is a long shot as the only thing I remember is that the movie was about two children who were next door neighbours. There was a string between their windows, and there were a bell at the each end of the string. I don’t really remember anything more than that, just that i felt good after watching it.

I know minimum one movie with that, but I need a little more to recognize what movies it was in.