How can we get my cats to accept a new kitten?

I had two siamese cats, I recently got another. (so now I have three We got the first cat fixed (a male) and the 2nd cat not fixed (she) and we wanted them to have kittens, so down the road we got another one. the first cat eventually got used to the 2nd cat, now that the third is here they are hissing and whining all of the time. we keep the two first cats in a screened in porch behind my house, while the new kitten is sleeping in a cage.
I do not know what to do!

The first 2 cats are being territorial and are presently viewing the new kitten as an 'intruder'on their territory.
They are not going to develop a peaches and cream friendship over night.
There is going to be an adjustment period of everyone getting used to each other and you will need to slowly introduce the kitten into the group of the other two.
Patience is the name of the game.

Let the older cat have run of the house along with the new one they may spit and hiss a little but the must establish a pecking order now or get rid of the new one, Mezzers are Very loyal like Dogs when treated right Mine actually comes to meet me when I get home and sleeps either on me or where she can sleep me. by locking the cats on the porch while you give the new one honored treatment you are betraying the trust of the older cats. and yes they remember. . Mine will actually chase the neighbors Black lab out of my yard. . . .