Keep the cats separated from each other. Your cat should be in a room by
herself with bed, food, water, and litter. You can then lock her cats in a
room by themselves and allow yours to wander the house/apartment. Gradually
expose the cats to each other while you are there. Break up any fights which
look like one cat might get hurt. This process should be gradual and over
time. It usually works.....have patience.......For three cats there should
be a minimum of 3 litter boxes. All should have their own food dished and
plenty of water dishes.
Gail

Well you'll have to seperate them in different rooms. The first week allow
them to sniff each other underneath the door. Then open it a crack so you
can allow the cats to see each other. If you have a carrier then I'd put
your cat in the carrier and allow the cats to sniff around it. You didn't
state whether your new wife is taking your home or you are taking hers. If
she is moving to your home then you might want to have her cats in the
carriers and allow your cat to sniff and move around them. Also allow your
cat to enter the rooom the other cats were confinded to and allow her to
sniff the other cats scents. It is highly advised you put her cats in a
carrier when she does this (and vice versa if it is her cats checking out
your cat's room)Also allow the cats to sniff the rooms where the other cats
have been. Then in about the second or third week allow them to interact
with each other under supervision. There are going to be spats but that is
expected. The cats will set their own rules and boundaries. Then they'll
either love each other or at the very least tolerate each other. Slow and
easy is probably the best way to introduce cats to each other.

Here are my suggestions.  This worked very well when I adopted Duffy and
brought him into my home where Holly was used to being "queen of her
domain."

(1) Take lots of time.  Plan to keep them in separate rooms for several
weeks.  Give the new cat several days to adjust to the room, then set aside
some time each day when you place the resident cats in one room and let the
new cat out.  Let her wander around the house to become acclimated to it and
also to spread her scent around.
(2) Make the new cat as comfortable as possible.  Alternate spending time
with the new cat and the resident cats -- and lavish lots of petting and
love on the other cat(s) as you enter or leave the room.  Have food, water,
litter box, and several toys in the room with the new cat.  Play the radio
at a low-to-moderate volume with classical or easy listening music -- it has
a soothing effect and will keep her company.
(3) Take it *very* slow before you try to bring the cats into physical
contact, especially under the circumstances you describe.
(3) If possible, after two or three weeks you should temporarily replace the
door to the room with the new cat with a screen door or one with a mesh
panel at the bottom.  This will enable the cats to get acquainted without
any possibility of fights.  You will probably notice some nervousness or
aggression at first, but it will slowly change to curiosity and then
interest.  Try to allow enough space under the door so you can place a
platter under the door with tuna fish or some other "treat" on both sides.
That way, the cats will become accustomed to eating in close proximity.  If
you will look at some of the pictures in the first album under my signature,
you will see pictures of how I introduced Duffy and Holly.  My cat, Holly,
had always been very aggressive toward any other cat, and we even called her
"the black tornado."  This slow, careful introduction worked.  I took a full
6 weeks, but they are now very companionable.
(4) Place several Feliway diffusers in your house -- one in the room with
the new cat and one or two in locations where the other cats spend a lot of
time.  Feliway has a calming effect, and the plug-in diffusers release
pre-measured amounts.  They are refillable.  Each refill lasts a little more
than one month.

Good luck!  This can be done and will be well worth the time it takes.

MaryL
(take out the litter to reply)

Photos of Duffy and Holly:      >'o'<
http://tinyurl.com/8y54 (Introducing Duffy to Holly)
http://tinyurl.com/8y56 (Duffy and Holly "settle in")

Thanks for all the advice--sorry I didn't follow up sooner, but things
have been busy around here.

For whatever it's worth, my wife is moving into my house.

One problem I foresee with isolating the cats is that her female has a
pathological case of Other Side Of The Door syndrome, and once tore
open a pad on her foot from pawing at a closed door.