An air carrier crew entered the SBGR SURF DEPARTURE in the FMC without selecting a transition to PCL and the FMC defaulted to MONDY; which was not a selectable transition. A track error resulted. The flight crew did not see on the paper chart that both the BGC and MONDY transitions terminated at PCL.

Narrative

The charted SURF departure transitions don't correspond to the airplane's Flight Management Computer (FMC) database. Specifically; the PCL transition shown in the database is not labeled on the chart. However; a depicted route to PCL overflies BGC so one might conclude that to overfly BGC with a continuation to PCL one should load the PCL transition; which we did. It turns out that by selecting the PCL transition the FMC loads the MONDY transition. The SURF departure actually has two different routings that both extend to PCL; the MONDY and BGC transitions. While perhaps not unique this is quite unusual. But because the entire departure to PCL is not depicted; the duplication is far from obvious and is only detected upon close inspection. I showed the chart to some other pilots and while all noticed the routing to PCL via BGC none noticed that the MONDY transition also extended to PCL. A traffic conflict led the controller to restrict our altitude and redirect us towards BGC. However; during flight even that became confusing since BGC wasn't on the loaded route. The best opportunity to prevent this error would be to step through the departure using the FMC LEGS page and the MAP mode at an appropriate scale. I do this for arrivals to unfamiliar destinations but haven't incorporated the technique into my departure process. Still; we had other chances to catch this discrepancy; but weren't up to it and flew the wrong transition. Fatigue was not a factor. We did; however; spend a lot of brain cells on an odd mechanical issue; an ocean of NOTAMS for the station and route and were scrambling to minimize a departure delay. Language barriers and the format for clearance delivery were problematic. I've observed that each SBGR controller seems to have his own format for issuing clearances. This exacerbates the language difficulties. So I insisted that all three pilots listen carefully to the clearance and discuss what we heard. While; following that discussion; I understood the clearance as taking us over BGC and PCL it never fully registered as a clearance to fly the BGC transition.