If it's two different tickets I don't think you're going to get around claiming your baggage and going through customs/immigration. Once you get into the baggage claim to get your bag you go through customs. And if I remember correctly, you actually go through immigration, then the baggage claim, then customs, then you can get to your next terminal. If you were on a connecting ticket you would check you bag again immediately in the baggage claim area, but since you don't have a connecting ticket, you'll need to go to the departures hall to do that.