Actually, if the European Cup was every three years, it wouldn't be before the World Cup every year... it would change year to year. Like if this one is the year before, then the next one would be two years after the World cup, and the one after would be one year after... then the one after that would be the same year? O_o
That's the problem with the Quidditch World Cup, though. It's mentioned as being every four years starting in 1473... but that would have made it in 1993 and 1997, not 1994 like in GoF. That would also make it 2001 and 2005... and the game takes place in 2004... Though, we could stretch it and say that they didn't have a World Cup in 1997 because of the turmoil that You Know Who caused, which would push it back a year to 1998, and the next would be 2002, and then 2006... that doesn't help. >_<
But we could come up with something like that (a quidditch European Cup). It's not mentioned in canon, but we could make something up for the game. Or an All-Star Game would be fun, too... so long as we get played characters in it.