Some dogs simply can't eat around other dogs. I have several who live quite happily together all day and get seperated at dinner time. It's not a big deal.

Kota is a resource guarder. It's not aggression. He may not be able to live with other dogs, he may need to have his own space to go to if he is in a multiple dog home. The behavior is manageable and over time, once he realizes that there will always be more toys, more food ect, it may diminish.

I would try playing the trade game with him. If he's guarding something, you trade him for something else. It helps teach them that they will always get enough.

Jean Donaldson has a great book on resource guarding. It's called MINE!! I got my copy off dogwise.com