You may look at your multicat household as one happy family; you love your cats equally and feel there shouldn't be any reason for fighting or squabbling. Many people believe cats to be solitary creatures. The social communities in the feline world vary, from very independent ferals who hunt and live alone to domesticated indoor cats who share very close quarters. In an outdoor environment, a cat's socialness will depend mostly on the availability of food and shelter. Some femals in a colony may form communal nests and nure one another's kittens. In multicat homes the cats may only tolerate on another, or some cats in the hierarchy may form very close bonds. Although there is a general hierarchy in your cat household, it's not a pecking order forever set in stone. I think of the feline hierarchy as the rungs of a ladder. Mounting behaviors in altered cats, whether between males or females, is often a dominance display. How a cat interacts with you doesn't influence his rank in the hierarchy. What determines a cat's place in the hierarchy? If you are breeding your cat or have found yourself with a pregnant female, socializing young kittens is very important.
I have had no experience w/throwing cats together and as we all know cats have their own unique personalities. Either they will get along or they won't. For me, I just like to introduce new animals to a large household of animals slowly. I have 3 cats and 2 dogs and this has worked for me. 
