Hershey has a few things not in his favor...declawed, and an adult kitty being introduced to more adult kitties. You should let him acclimate to his surroundings for a while, and then put him in a carrier with some Found Cats bedding in it. Put the carrier in the room with the rest of the gang for a short time, and let him hiss all he wants. Another thing you can do is exchange bedding daily, Hershey's switched with Found Cats beds, and let him get used to the smells of the other kitties. He feels scared and defenceless right now. Can you blame him? Hang in there Gary, but take it much slower with the introductions. Siamese are highstrung to begin with. Maybe a little Rescue Remedy for all will help calm things a bit. Or some Feliway plugins.