  Microcavity-polaritons in two-dimensional lattice geometries have been used
to study a wide range of interesting physics. Meanwhile, organic materials have
shown great promise on the road towards polaritonic devices, as the strong
binding energy of their Frenkel excitons permits room temperature condensation
and lasing. Whilst there are theoretical treatments of the condensation
processes in planar organic microcavities, models of lattice geometries are
lacking. Here, we introduce a model for describing the dynamics of lattices of
zero-dimensional organic microcavities, where the dominant condensation
mechanism involves the emission of a vibrational phonon. The vibronic resonance
provides a tool for targeted condensation in a particular eigenmode of the
system, which we highlight by examining a dimer and a dimerised chain. For the
dimer, we observe a double resonance in the condensation efficiency that arises
from tuning the condensate-reservoir detuning in to resonance with either the
symmetric or antisymmetric mode. This selective condensation was also exploited
in the dimerised chain, to condense the system into the topological edge states
under homogeneous pumping of all cavities. We also showed an interesting
signature of nonreciprocal transport when pumping a single cavity in the chain,
where the direction of propagation depends on the sublattice being pumped.
