Vector meson dominance (VMD) was a pre-QCD treatment of the hadronic content of the photon in which the propagator went something like this:
My understanding is that it is applicative to soft processes.
A similar treatment appears in polarized semi inclusive deep inelastic scattering (DIS) experiments:
$$\vec e(\vec N, e'\pi^+\pi^-)N $$
$$\vec e(\vec N, e'K^+K^-)N $$
Here the $\vec e$ and $e'$ serve to define a (polarized) virtual photon, and the detected pions (kaons) reconstruct to a rho (phi) meson that is the photon that has coherently scattered from the polarized nucleon (or nucleus). The invariant mass of the final state may also indicate a resonance, but again: that's a coherent process, not hard scattering off point partons.
(What makes this reaction interesting is that the dependence on the decay plane angle defined by the pseudo scalar mesons relative to the electron scattering plane is sensitive to the vector meson polarization....all while the virtual photon polarization is known).