Lore wise, the various types of Werebeast live in their own different environments. They are however individuals and could move if they desired(thats my stance) and it is not impossible in my view to find at least one of each strain in one province, though the odds of this are very unlikely. Some would just have a much better chance of survival in their native environments. And having them all in one province for a game(Skyrim) is a overhaul. This would be pluasable if we were able to go to the hunting grounds.
They would also not be in groups competing against each other. First of all they are all rare and much more likely to to be independant. Second they have more in common than they have differences and really have no need to compete with one another, in fact they have been known to work together under Hircine for the Hunt. And this isn't D&D. None of the strains brings with it any specific attitude or alignment. Any one of any background, creed, emotional preference could be infected by any of the strains and retain the same disposition.
It would take place in the Hunting Grounds.
And there's nothing in the lore that states there is no animosity between the strains, or that a werewolf and wereboar or whomever would be predisposed to work together.
The two most recent examples of Lycanthropy in the games have involved "covens" of werewolves, one being the small army Hircine amassed on Solstheim, and the other being the Companions, it stands to reason that the same could be said, for instance, of Werelions or Werecrodiles.
Not to mention that creatures of a similar variety flocking to eachother is just common sense, regardless of the initial fact that lore supports it.
The examples of solitary werebeasts (like the quests in Daggerfall) usually end poorly, with the creature being hunted.
Also noting that werecreatures (and creatures of any kind, for that matter) are very territorial.
Obviously there would be tension if say, a group of Werebears moved into Whiterun.
And if you'd still like to argue that these groups wouldn't come to blows on their own, then Hircine could be the catalyst, setting up a hunt where the prize is the distillation of their strain in all areas of Tamriel, and an increase in power (stat buffs, obviously).
Werewolves can currently be found in every province, which could be attributed to wolves being adaptable creatures, but, adaptation means nothing to a werebeast as it's a purely magical, not biological transformation.
Furthermore, Hircine can supersede the desires of a werebeast, possibly even when they aren't even in their beast form, and thus the intentions of the individual does not matter.
If Hircine wanted all the werevutures and weresharks in Skyrim, they would come.