Introduction of 1 Male to 2 Females

Question
I have a 6 year old male cat.  I got him from the SPCA in Houston Texas, he is a great cat.  Morpheus, Meows at the door quite a bit but other than that i have no complaints, he has been a great companinon.  I moved to Dover, New Hampshire where i met my fiance and she has now moved in with me.  She brought with her her two 10 year old, 5 pound female cats, which are sisters.  All 3 cats have been together for about 11 days now.  The more affectionate female Sage really doesnt care about Morpheus too much, but the other Cat Porsha chases him and trys to attack him. Keep in mind Morpheus is a big Cat prob 16 pounds and they are only about 5-6 pounds.  Morpheus has been pretty calm about the situtaion, but im afraid he will turn and really hurt her kitty if she keeps trying to chase and attack.  Any reccomedations on what to do to make everyone more comfortable?  Thanks for your help!  

Answer
Hi Andrew.  Though I'm sure you and your fiance will hate to do it, you should probably limit Porsha to one room for now.  This is going to make it easier to adjust to her new home.  Cats do better with small spaces at first - a whole house overwhelms many of them.  Too many places a potential enemy could hide.

You should introduce Morpheus and Porsha slowly.  Most cats take about two weeks to introduced when done properly.  Trying to rush it can actually cause it to take longer.

Instead of allowing them to mingle freely, use scent transference to get them use to each others' scents.  Rub one of them down with a towel, and then allow the other to smell it, and vice versa.  If Porsha seems very comfortable with her room and appears curious about exploring the rest of the house, then you can put Morpheus in the room for half an hour and allow Porsha to roam.  This will also allow them to get used to one another's scents.  

Another great idea is to feed Porsha and Morpheus on opposite sides of a door.  They'll be aware of each other's presence on the other side, but it won't be so scary without being able to see each other, and eating will be a positive experience they can come to associate with one another.

Since all the cats are older and set heavier in their ways than younger cats, I'd do this for a couple weeks before trying to introduce them face-to-face again.  Start with short visits, say meal time in the same room, but at opposite ends.  And then you can move their bowls closer each day until they're eating peacefully side-by-side.

Once the grumbling dies down, you can start giving them more freedom, but I wouldn't leave them alone together until you see no more signs of fear or aggression.  Always separate them when you aren't home to prevent a fight.  This can leave you with a situation worse than the one you started with.