The authors have measured the intensities of several diffuse interstellar bands in intermediate resolution spectra (0.35 - 0.65 Å) of heavily reddened early-type stars in three associations: Cas OB6, Be 87, and Cyg OB2. The extinction is attributed mostly to material at intermediate densities between molecular clouds and the diffuse medium. The degree of correlation with EB-V separates the lines into at least two groups. The analysis of line profiles reveals a wide variety of shapes even among strongly correlated lines, ranging from a nearly symmetric Lorentzian for λ6284 to a highly complex multiple structure of λ6203+λ6205. These observational facts appear to preclude the origin of the lines in bulk solid particles and favor their explanation as vibronic transitions in large molecules.