[lowbridge]

Hope for the best. It will take quite a while for all four cats to get along.

It's best if you have all four cats spayed and neutered. They'll be calmer around each other that way.

[Syberyenta]

I was going to suggest that you overfeed them and hope for the best. How can you be sure that they won't get along?

[Taylor42]

I did this several years ago when my wife and I blended our cat families. Take the new cats and place them in a room by themselves with food and litter. (Mine hid under a bed for 24 hours.) Give them time to adjust to the new location. After a day or so open the door and let them out.

In our case, everybody adjusted fine. But it does take some time.

[beyond the sea]

It's best if you have all four cats spayed and neutered. They'll be calmer around each other that way.

Yes, they all are "fixed", but they're still cats!

Thanks!