On United.com this morning looking at Saver Awards from IAH to HNL and found one that is United to PHX, then US Airways to HNL. I can select the seats on the United flight, but not on the US Airways as it says, "Advanced seats assignments are not available through united.com, please see an airport agent during check-in to receive your seat assignment." This flight would be for my wife and I, should we worry that we will not be seated together? Lastly, is there any way to secure a seat assignment before the day of check in?