We are considering a two week trip LHR-IAH. If we go, DH will be going LHR-IAH with us, will spend a week in Texas, then fly IAH-RTB for the last week, while the girls and I spend the whole two weeks at Grandma's.
Upon his return to IAH from RTB, the girls and I will meet him in Houston and all return to LHR together.
We chose United solely for the direct flights to both IAH and RTB. I am comfortable booking this online, but I will obviously have to book myself and the girls on one itinerary and book DH separately.
Once I do this, can I just call United and get our reservations linked, so they know we're doing the LHR-IAH-LHR portions together? Thanks!

Yes, just call them once you have made the reservations.

United outsources all their customer service to India. I have had difficult experiences calling them - since some seem to read from a script. If this happens, call back until you get someone who actually is able to be helpful.

Oh dear lord gail, thanks for the heads-up - I really struggle with the Indian accent for some reason, and it's enough to make me want to jam pencils through my eardrums. I shall strive to be patient!!

I've had good luck with United customer service - occasionally I have to call back and get another person, but it isn't so bad.

You can "link" itineraries on United.com. Whether it the same as having an agent do it, or wehther either will even have an affect, are separate matters.

Thanks rkkwan, when I get them booked I'll check that out.

Please keep in mind that the "linking" is not the same thing as having all the reservations on one record. The different itineraries will be on separate PNRs with distinct record locators.

I was just hoping to have some sort of connection between the two, in the event that there's a cancellation/flt change/etc, United knows that DH and the girls and I are travelling together. Is "linking" sufficient for this?

"United knows that DH and the girls and I are travelling together."

How does United know this? Do you think they know this because you are listed in each other's profiles or have you already linked the reservations? Once you have linked the reservations, that is all you can do.

Sorry, Kathie, perhaps I wasn't clear - I want to link the reservations so that United knows that we are travelling together. I am trying to find out if that's the correct term and the right thing to do to get what I want. We haven't even booked the tickets yet.

Sorry, I misunderstood you.

Yes, what you want is to have the reservations linked. Because not all of the flights for your family are the same, they cannot be on the same reservation number, but the linking will tall them you are traveling together.

Thanks - that's what I was hoping!

Actually, that is a misperception. The linking is nothing more than a note in the comments section of the record, and it is not "computable" meaning that if the automatic rebooking, reseating, etc. processes occur in the event of an irrops the two reservations are processed separately. Unfortunately, once the tickets have been issued there is no way to "link" them into in a single record. This means that if there does happen to be some irrops that results in a change of flights, be sure you check carefully and probably contact the airline and point out that you are traveling together.