I have known Couver long enough to say with a doubt that he does not have a vicious bone in his body! I sincerely believe that the other non-toy dogs are a threat to Couver and his friends. Couver is the leader of the pack and hes just trying to protect all his fur friends
I think if you stay close, an immediate NO when he starts to "attack", quickly pick him up and leave he will get the hint...like concretegirl said...!!!