How can I get these cats to get along with each other?

I have three cats: two boys , one girl. Two are 7 years old and the other one is eight years old. They were the best of friends until i got two girl kittens (all the cats are spade by the way), all of a sudden the two male cats start fighting. One just stays in a room all day and never leaves, the other wanders around all high and mighty. Meanwhile the older girl cat, hates one of the kittens and always attacks her when she sees her.The other kitten is too cautious she jumps if you make any sudden movements. How do i get these cats to get along with each other??

Like orksecurity said, they're going to need to pick out their order and social structure, and there's not a whole lot you can do.  You can provide hiding spaces and climbing trees so that each cat has the possibility of escaping and having some alone time.  You also should monitor food and water to make sure each one is getting enough.
Monitor litter boxes too, and/or consider setting up an additional one. I've known some cats to get terratorial about those.
NachoMahma7 years ago
.  Just to re-inforce what orksecurity and AngryRedhead said:
.  Let the cats work out the pecking order. It will be noisy and you might think they are killing each other, but, if you get involved, it will just be worse when you aren't around to keep the peace.
.  When they work it out, respect it. Top cat gets fed first, most of the attention, &c.
.  Some critters just don't get along. You may need to thin the herd a little bit.
orksecurity7 years ago
They had worked out who out-ranked who (including the fact that the humans outrank them), and then you complicated things. They're going to have to work out the dominance order again.

Note that which cats you pay the most attention to does figure into this. The kittens are cute, but they're the newcomers; you need to make sure the older cats get at least as much attention as they ever have and at least as much as the kittens do. Yes, they keep score.

You could try giving up the two kittens and hoping that things settle back into the old patterns, of course.

But outside of those suggestions, I don't know of anything a human can do about that except wait it out. You can try water-gunning them whenever they start fighting, but I suspect they'll just learn not to get caught at it. They're cats, after all; obedience isn't all that high on their list of virtues.

(I prefer cats to dogs myself... but I wouldn't have risked bringing in more than one new cat at a time, in a household that already had cats in residence. It's a bit different if they all come in at once, so nobody has seniority.)