Adopted stray cat problems (continued)

This is an update on the stray cat saga told here over a month ago.

I've been living with three cats who are free to go in and out of the
house at will, for nearly three years now. The older two were once
confined, but the youngest one, nearly age two, has never been
confined.

To recap, a stray unneutered male created a big disruption by coming
in the house at night, all through the winter. I shooed him away
many times, but he became bolder, and I became less willing to deny
him food and warmth. But then, not having done it for the first
few months of sneaking in, he started 'marking his territory' this
spring, and that caused two cats to stop coming in the house at all,
and the youngest one to jump around from one piece of furniture to
another, to avoid the marked places. He too started staying outside
most of the time.

So I decided to take the stray cat across the river and leave him to
find a way to survive, hopefully. I did that, but went back and got
him after an hour because I was overcome with guilt and remorse. The
cat was where I had left him with food and milk, just sleeping.

Not willing to take him to an animal shelter, where he would be killed
eventually, I decided to have him neutered and hope that he would stop
marking territory, though that result is not assured for an adult.
So he was neutered and had a rabies shot and I gave him an Advantage
flea treatment. For the next two weeks or so I was able to make him
content by feeding him downstairs, and he did not come upstairs. He
knew just to come in for food and sleep downstairs.

But that didn't last. Luckily he -did- stop marking his territory, but
he started acting like a kitten and following me everywhere, always
wanting to be petted and wanting to snuggle up to me wherever I was.
That was pretty much OK, except that the other cats kept their distance
from him. It was difficult to arrange to have time with the other
cats, but the situation gradually got better.

Then the big trouble started. Though the other cats were gradually
getting used to him, he started being aggressive toward the younger
male, chasing him away. The older male never would get close enough
to him to have a confrontation, and the older female is dominant over
the stray, so there's no problem with her. Interestingly, if she is
present when the stray and the younger male have a confrontation,
she will intervene effectively. At other times I try to intervene,
but not very effectively. I can stop the stray's aggression by yelling
and clapping my hands, but I scare the other cat too, so he runs away.
In any case the aggression by the stray toward the younger male
continues to flare up. It's intolerable and horrible, and I don't
seem to have any hope of stopping it. The stray cat is very docile
with me, making me think he was not originally a stray. But he is not
docile with the other male cats.

As I write this, the younger cat was last seen running out into the
rain after I made a situation worse by trying to prevent a confrontation.
The stray is locked up in a bedroom with food, milk, and a litterbox
and he will stay there until I am able to feel good about the other
cats being dry and fed.

Other than perpetually keeping the stray cat locked up, I see no way of
solving this problem. I thought the primary flaw in my plan was that
the neutering might not stop the cat from marking territory. I was
very lucky on that account, but the aggression of the stray toward my
youngest makes the overall problem worse now than ever.

I suppose some will say that I have shown why it is not a good idea to
allow cats to go in and out of the house at will. They may be right,
but I'm still not willing to confine my three adopted cats. I'm only
willing to confine the stray cat, if that is the only way to solvc the
problem, but it's not a good permanent solution.

Calvin Rice