  There are several wide field galaxy and cluster surveys planned for the
nearest future, e.g. BOSS, WFMOS, ADEPT, Hetdex, SPT, eROSITA. In the simplest
approach one would analyze these independently, thus neglecting the extra
information provided by the cluster-galaxy cross-pairs. In this paper we have
focused on the possible synergy between these surveys by investigating the
amount of information encoded in the cross-pairs. We present a model for the
cluster-galaxy cross-spectrum within the Halo Model framework. To assess the
gain in performance due to inclusion of the cluster-galaxy cross-pairs we carry
out a Fisher matrix analysis for a BOSS-like galaxy redshift survey targeting
luminous red galaxies and a hypothetical mass-limited cluster redshift survey
with a lower mass threshold of 1.7x10^14 M_sun/h over the same volume. On small
scales cluster-galaxy cross-spectrum probes directly density profile of the
halos, instead of the density profile convolved with itself, as is the case for
the galaxy power spectrum. Due to this different behavior, adding information
from the cross-pairs helps to tighten constraints on the halo occupation
distribution. By inclusion of the cross-pairs a factor of ~2 stronger
constraints are obtained for sigma_8, while the improvement for the dark energy
figure-of-merit is somewhat weaker: an increase by a factor of 1.4.
