  Rare B decays of the type $b \to s~\ell^+\ell^-(\nu\bar\nu)$ are analyzed in
a generic scenario where New Physics effects enter predominantly via $Z$
penguin contributions. We show that this possibility is both phenomenologically
allowed and well motivated on theoretical grounds. The important role played in
this context by the lepton forward-backward asymmetry in $B\to K^*\ell^+\ell^-$
is emphasized.
