  We extend an approximation earlier developed by us for the single-impurity
Anderson model to a full-size impurity solver for models of interacting
electrons with multiple orbitals. The approximation is based on parquet
equations simplified by separating small and large energy fluctuations
justified in the critical region of a pole in the two-particle vertex. We show
that an $l$-orbital model with most general interaction is described within
this approximation by $4l^{2}\times 4l^{2}$ matrices and is Fermi liquid in the
metallic phase. We explicitly calculate properties of a paramagnetic solution
of a two-orbital Hubbard model with a Hund exchange and orbital splitting
within the dynamical mean-field approximation. We trace the genesis of a
metal-insulator transition induced by a crystal field and vanishing of the
Kondo quasiparticle peak in strongly correlated orbitally asymmetric systems.
