I've wrestled with this one before and have, at least on one occasion, kept my RTW as is and purchased a 2nd, independent R/T for the "back-tracky-parts" stuffed in the middle of my RTW. For said itinerary I still "saved" ~ $2,500 by doing it this way. (For me a 29k RTW Business Class costs $5,670 + tax, which for most of my itineraries is usually 50-60% of a comparable non-RTW fare.