  We study the hadronic molecular structure of hidden heavy pentaquarks - new
exotic states composed of charmed/bottom baryons and $D(D^*)/B(B^*)$ mesons.
Based on the observation of three pentaquark candidates $P_c^+(4312)$,
$P_c^+(4440)$, and $P_c^+(4457)$ by the LHCb Collaboration we consider the
classification of possible flavor partners composed of charmed baryons and
$D(D^*)$ mesons within the hadronic molecular approach. We extend this
classification to the bottom sector. Using phenomenological Lagrangians we
construct baryon-meson bound states governed by the Weinberg-Salam
compositeness condition. As an application we consider strong two-body decays
of the new exotic states into a light baryon and $V=J/\psi,\Upsilon$ or
$P=\eta_c,\eta_b$ mesons. Results are presented in the heavy quark limit.
