Attempt at Constructing a Model of Grand Gauge-Higgs Unification with Family Unification

We discuss a possibility whether a model of grand gauge-Higgs unification incorporating family unification in higher dimensions can be constructed. We first extend a five dimensional $SU(6)$ grand gauge-Higgs unification model to a five dimensional $SU(7)$ grand gauge-Higgs unification model compactified on an orbifold $S^1\mathrm{/}{Z}_2$ to obtain three generations of quarks and leptons after symmetrybreaking of the larger family unified gauge group. A prescription of constructing a six dimensional $SU(N)$ grand gauge-Higgs unification model including a five dimensional $SU(7)$ grand gauge-Higgs unification after compactifying the sixth dimension on an orbifold $S^1\mathrm{/}{Z}_2$ is given. We find a six dimensional $SU(14)$ grand gauge-Higgs unification model with a set of representations containing three generations of quarks and leptons.