  A unification of left-right $\rm{SU}(3)_\rm{L}\times \rm{SU}(3)_\rm{R}$,
colour $\rm{SU}(3)_\rm{C}$ and family $\rm{SU}(3)_\rm{F}$ symmetries in a
maximal rank-8 subgroup of ${\rm{E}}_8$ is proposed as a landmark for future
explorations beyond the Standard Model (SM). We discuss the implications of
this scheme in a supersymmetric (SUSY) model based on the trinification gauge
$\left[\rm{SU}(3)\right]^3$ and global $\rm{SU}(3)_\rm{F}$ family symmetries.
Among the key properties of this model are the unification of SM Higgs and
lepton sectors, a common Yukawa coupling for chiral fermions, the absence of
the $\mu$-problem, gauge couplings unification and proton stability to all
orders in perturbation theory. The minimal field content consistent with a
SM-like effective theory at low energies is composed of one $\mathrm{E}_6$
$27$-plet per generation as well as three gauge and one family $\rm{SU}(3)$
octets inspired by the fundamental sector of ${\rm{E}}_8$. The details of the
corresponding (SUSY and gauge) symmetry breaking scheme, multi-scale gauge
couplings' evolution, and resulting effective low-energy scenarios are
discussed.
