What was this incest movie?

I just remembered this movie that was playing at the Philadelphia International Film Festival several years ago (sometime around 2000) that I missed, but now I can't for the life of me remember the name of it, just the vague description from the festival book.

It was European, I think, but I don't remember what country or language. It was about a brother and sister who once had an incestuous relationship when they were children, but eventually grew apart... or didn't. The main plot involved them sabotaging each other's current spouses/significant others, as for some reason, both of their families had to live under the same roof. I don't know why this description has stuck with me, but now I kind of want to try to rent the film if possible so I can forget it. (My hopes for the film's quality aren't high.)

Also, if you did see this movie, was it actually good or was it terrible?