Neuturing would probably help abit if they aren't fixed yet. Are they both male rabbits? And how old are they? They problem with buying two male rabbits, is they most likely will never get along with one another, especially if they aren't introduced at a young age.
I am guessing that you've had your first rabbit for awhile now and he is sexual mature, because of the way he is acting. He definately thinks the house is his, and the new rabbit is competition, so to speak.
It's nice to hear you have seperate cages for them, lots of people don't think that far ahead when they get a second rabbit.
I doubt the situation will improve much. How long have you had the new rabbit?
Personally I would fix them both first, (or atleast your older one if the other one is too young) give it a few weeks and see if there's been any change in your rabbits attitude. If he is still acting agressively, you might have to consider a new home for the little one. Or you could keep both and never let them out at the same time, maybe keep them in seperate rooms.