lnternational/Domestic flight indicator in Sabre reservation

When using Sabre APIs, is there any reliable indicator available in a Sabre TravelItineraryReadRS (or GetReservation) or other API that indicates whether a flight is international or domestic? I want to avoid adding complexity and having to maintain a separate list of airport codes and countries if possible, and instead just use an indicator from a response.

I've checked <FlightSegment> in <PTC_FareBreakdown> but nothing seems to indicate internationality:

<tir39:FlightSegment ConnectionInd="O" DepartureDateTime="02-24T13:00" FlightNumber="123" ResBookDesigCode="E" SegmentNumber="1" Status="SS">
    <tir39:BaggageAllowance Number="01P"/>
    <tir39:FareBasis Code="AFB112"/>
    <tir39:MarketingAirline Code="VA" FlightNumber="123"/>
    <tir39:OriginLocation LocationCode="BNE"/>
    <tir39:ValidityDates>
        <tir39:NotValidAfter>2019-02-24</tir39:NotValidAfter>
        <tir39:NotValidBefore>2019-02-24</tir39:NotValidBefore>
    </tir39:ValidityDates>
</tir39:FlightSegment>

and also checked in <ReservationItems><Item>, e.g.:

<tir39:Item RPH="1">
    <tir39:FlightSegment AirMilesFlown="0466" ArrivalDateTime="05-18T14:40" DayOfWeekInd="6" DepartureDateTime="2019-05-18T13:05" SegmentBookedDate="2018-12-21T11:20:00" ElapsedTime="01.35" eTicket="true" FlightNumber="0529" NumberInParty="01" ResBookDesigCode="E" SegmentNumber="0001" SmokingAllowed="false" SpecialMeal="false" Status="HK" StopQuantity="00" IsPast="false" CodeShare="false" Id="123">
        <tir39:DestinationLocation LocationCode="SYD" Terminal="TERMINAL 3 DOMESTIC" TerminalCode="3"/>
        <tir39:Equipment AirEquipType="21B"/>
        <tir39:MarketingAirline Code="QF" FlightNumber="0529">
            <tir39:Banner>MARKETED BY QANTAS AIRWAYS</tir39:Banner>
        </tir39:MarketingAirline>
        <tir39:Meal Code="L"/>
        <tir39:OperatingAirline Code="QF" FlightNumber="0529" ResBookDesigCode="E">
            <tir39:Banner>OPERATED BY QANTAS AIRWAYS</tir39:Banner>
        </tir39:OperatingAirline>
        <tir39:OperatingAirlinePricing Code="QF"/>
        <tir39:DisclosureCarrier Code="QF" DOT="false">
            <tir39:Banner>QANTAS AIRWAYS</tir39:Banner>
        </tir39:DisclosureCarrier>
        <tir39:OriginLocation LocationCode="BNE" Terminal="DOMESTIC" TerminalCode="D"/>
        <tir39:UpdatedArrivalTime>05-18T14:40</tir39:UpdatedArrivalTime>
        <tir39:UpdatedDepartureTime>05-18T13:05</tir39:UpdatedDepartureTime>
    </tir39:FlightSegment>
</tir39:Item>

and although these have origin/destination airports, neither indicate whether the flight is international or not, and the terminal name is not reliable as an indicator.

<PriceQuotePlus> has a DomesticIntlInd attribute that initially looked useful:

<tir39:PriceQuotePlus DomesticIntlInd="I" PricingStatus="S" VerifyFareCalc="false" ItineraryChanged="false" ...>

but PriceQuotePlus and therefore DomesticIntlInd does not seem to be present in all circumstances. e.g. I have TravelItineraryReadRs responses where there is no PriceQuotePlus element, but still contains ReservationItem/Item/FlightSegment elements that I need to be able to identify as International or Domestic. Not only this, but as an example, I have a reservation where "DomesticIntlInd" is set to "I" in a reservation that does not have an International flight (it has only one flight, and that flight is domestic (BNE-SYD)).

Any other thoughts on where I might find a reliable international flight indicator or is this functionality simply not available?

Solution

Sabre does expose a City Pairs API that includes country codes for each airport, which you could use to infer whether a flight started and ended in the same country.

They also expose this as a list that you could build into your own data table, but the API would probably be more futureproof.

The current file can be found here, but I don't know if that link will work forever.