  With the apparent discovery of the Higgs boson, the Standard Model has been
confirmed as the theory accounting for all sub-atomic phenomena. This
observation lends further credence to the perturbative unification in Grand
Unified Theories (GUTs) and string theories. The free fermionic formalism
yielded fertile ground for the construction of quasi--realistic
heterotic--string models, which correspond to toroidal Z2xZ2 orbifold
compactifications. In this paper we study a new class of heterotic-string
models in which the GUT group is SU(6)xSU(2) at the string level. We use our
recently developed fishing algorithm to extract an example of a three
generation SU(6)xSU(2) GUT model. We explore the phenomenology of the model and
show that it contains the required symmetry breaking Higgs representations. We
show that the model admits flat directions that produce a Yukawa coupling for a
single family. The novel feature of the SU(6)xSU(2) string GUT models is that
they produce an additional family universal anomaly free U(1)symmetry that may
remain unbroken below the string scale. The massless spectrum of the model is
free of exotic states.
