I have a question about possible combination of reservations. As I prepare to book a trip to LAS in April, I am thinking about redeeming miles for my wife's and son's ticket's from my Silver OP account, and purchasing my own ticket if the price is right in order to earn miles, or to just redeem miles for all three tickets.

I know that if I book all three tickets with miles at the same time, then my wife and son are extended my elite benefits of seat selection, baggage allowance, etc. If I buy their tickets with miles, and my ticket separately with cash, is there a way to combine the reservations into one, with the primary goal that all three of us can travel with elite benefits?