Unveiling the whole from its parts or to see the forest from the trees

In our quest for large organic molecules in the interstellar/circumstellar medium, the main difficulty is to disentangle their spectral signatures among the observed forest of bands. We propose a new approach to the problem, by defining a number of key transitions coming from parts of the whole molecule and that would characterize its fingerprint. If these key transitions are observed together in the same astrophysical target, it may be that we are detecting the whole from its part.