Something I have noticed a lot in Triwizard fics is that whenever Hogwarts is involved, no matter what the year, the three schools competeing are always Hogwarts, Beauxbatons, and Durmstrang. Does this mean only these three schools ever compete against one another. It is reasonable to assume that other schools in Europe take part in the Tournament, as we see in HPB, the Tournament is getting ready to take place at another school?

So what are you thoughts? Does Hogwarts always compete against its set rivals, or could it be possible that in other years, other schools would compete against them?