The Red MSX Source (RMS) survey has identified a large sample of massive young stellar objects and ultra compact HII regions from a sample of ~2000 MSX and Two Micron All Sky Survey (2MASS) colour selected sources. Using a recent catalogue of molecular clouds derived from the Boston University-Five College Radio Astronomy Observatory (BU-FCRAO) Galactic Ring Survey (GRS), and by applying a Galactic scaleheight cut-off of 120pc, we solve the distance ambiguity for RMS sources located within 18{deg}<|l|>54{deg}. These two steps yield kinematic distances to 291 sources out of a possible 326, located within the GRS longitude range. Combining distances and integrated fluxes derived from spectral energy distributions, we estimate luminosities to these sources and find that >90 per cent are indicative of the presence of a massive star. We find the completeness limit of our sample is ~10^4^L_{sun}_, which corresponds to a zero-age main-sequence star with a mass of ~12M_{sun}_. Selecting only these sources, we construct a complete sample of 196 sources.