Have you checked the cost of a multi-city / open jaw ticket for San Antonio to Guatemala to Phoenix?

Yeah, for a variety of reasons this works better. thanks!

p.s. meaning I'm still looking for an answer!

What did the cost turn out to be for San Antonio-Houston-Guatemala City-Houston-Phoenix? Does it seem reasonable to you?

I really appreciate the ideas, but I'm really just looking for an answer to my original question. Cost isn't the only factor. Thanks!

No issue at all. And since you need to claim bags at IAH anyways, you don't even have to short-check your bags (and get questioned why) when checking luggage in Guatamala.

Sorry. I misread "this works better" to mean that you were going to take Alan Row's suggestion, and then couldn't figure out why you were still looking for an answer to your first question.

Are you entering Continental FF numbers for both itineraries? Do you risk being flagged for not posibly being able to take simultaneous flights from Houston to San Antonio and Phoenix?

Ooh good point about the bag-checking, thanks! But Jeff you raise a good point about trying to get credit for FF miles. WIll Continental "flag" me as a bad passenger?!

If you worry about it, don't put in your FF number when booking the IAH-PHX. Don't even log in to your account at continental.com. Just give you FF number before you board the actual flight.

Technically, you are proposing to violate the terms of the contract you agree to when you buy the ticket, and they have the right to charge you for the itinerary you actually flew.

Practically, I've never heard of them doing that.

I dumped the last leg of a United flight (ORD to PIA I think it was). Nothing happened. I did not have checked bags to worry about. Weather was bad, and I had another option for getting to PIA without hanging out at OHare for hours.

People throw away the last leg of tickets all the time. They're not supposed to, but they do. This situation is complicated by then trying to take another flight at the same time on the same airline as that discarded ticket portion. Will Continental see that and cancel your reservation?

I think that many (all) of the preceding responses have missed a key point: the OP proposes to be ticketed on the same airline for concurrent flights.

If it weren't for the concurrent flight, then it's the obvious answer that you've been given: as a practical matter, it's ok to discard the final legs of any ticket, especially if you're not making a practice of it. However, the real question is whether CO's software is sophisticated enough to flag concurrent flights.

I do not know the specific answer. I do know that I have had ticketed reservations for concurrent flights on American, and their software automatically canceled one of the flights. So, there is certainly a risk that one of the flights would get canceled.

Right. That's what I pointed out just above you.

Why not simply book a ticket SAT-IAH-GUA-IAH-PHX. Why not book the travel desired and avoid this risk entirely of having any reservations cancelled? Is that itinerary really that much more expensive than the cost of the round-trip ticket plus the one-way ticket?

Can't you fly from Houston to PHX on another airline? If you don't mind taking a taxi from IAH to Hobby, you can get on a Southwest flight really easily for not much money.

If you are set on doing this, why risk Continental picking up on the overlap? Even if you don't use your FF #, what about the credit card info? Would it connect the dots using that number??

I really appreciate all the replies. You are right that the risk probably outweighs the benefits! I'm glad to know I can throw away the last leg of a SAT-GUA roundtrip through Houston, but I probably won't risk having 2 concurrent flights on Continental.

Thanks for all the advice!

Do you already have the SAT-GUA-SAT itinerary booked? If not, just search an itinerary for multiple destinations, SAT-GUA and return GUA-PHX. I just did a quick check and it works.
If you are already booked, you would probably have to pay a penalty fee to change unless you are within 24 hours of the original booking when you can cancel for a full refund without penalty.