  We divide some of the observed diffuse interstellar bands (DIBs) into
families which appear to have spectral structures of single species. Three
different methods are applied to separate such families, exploring the best
approach for future investigations of this type. Starting with statistical
treatment of the data, we found that statistical methods by themselves give
insufficient results. Two other methods of data analysis ("Averaging EWs" and
"Investigating the figures with arranged spectrograms") were found to be more
useful as tools for finding the spectroscopic families of DIBs. On the basis of
these methods, we suggest some candidates as "relatives" of 5780 and 5797
bands.
