  Non-abelian discrete symmetries are of particular importance in model
building. They are mainly invoked to explain the various fermion mass
hierarchies and forbid dangerous superpotential terms. In string models they
are usually associated to the geometry of the compactification manifold and
more particularly to the magnetised branes in toroidal compactifications.
Motivated by these facts, in this note we propose a unified framework to
construct representations of finite discrete family groups based on the
automorphisms of the discrete and finite Heisenberg group. We focus in
particular in the $PSL_2(p)$ groups which contain the phenomenologically
interesting cases.
