I've often found Orbitz is the only way to book some multi-airline itineraries that ITA finds. That said, I can't stand Orbitz or their customer service - their phone folks just like transferring me between departments to help, and their sudden decision to occasionally only update tickets at mytripsandmore instead of their own web site drives me insane. Is there any alternative that can "force" more complicated multi-airline?

For example, I just had to book a trip that was outbound as AS-DL (not codeshared, but listed separately), with return as US-US. Times were great compared to what any airline/codeshare offered alone, price was similar to booking one airline alone, and I could stand to earn miles on both AS + UA, so worked for me.

However, I was only ever able to find this routing on Orbitz (and ITA) - not Expedia, not Travelocity, not CheapoAir, not Kayak, not airlines directly.
For all of these, tried doing just as a roundtrip + breaking into individual city pairs for each segment. One-ways priced out 3x as much as booking the combo as one trip on Orbitz, so couldn't do airlines direct, which I usually prefer to do.

This isn't the first time I have seen this effect w/ Orbitz finding trips (and having bookable) I can't recreate elsewhere.

Any ideas or suggestions? I ended up booking via Orbitz, but would love a second option for these.