Try putting the aggressive one in a smaller enclosure with two hides of his own with a proper heat gradient. Leave him alone for a week or so. Don't try to feed him and don't try to handle him. After a week, try feeding him. If he doesn't eat, wait another week. Keep doing this until he does eat. Don't try to handle him until he has eaten for you. Of course, wait the requisite 24 to 48 hours after his first meal until you try handling him.