  Following the scanning methods of arXiv:1910.04530, we for the first time
systematically construct the $N=1$ supersymmetric $SU(12)_C\times SU(2)_L\times
SU(2)_R$ models, $SU(4)_C\times SU(6)_L\times SU(2)_R$ models, and
$SU(4)_C\times SU(2)_L\times SU(6)_R$ models from the Type IIA orientifolds on
$\bf T^6/(\mathbb Z_2\times \mathbb Z_2)$ with intersecting D6-branes. These
gauge symmetries can be broken down to the Pati-Salam gauge symmetry
$SU(4)_C\times SU(2)_L \times SU(2)_R$ via three $SU(12)_C/SU(6)_L/SU(6)_R$
adjoint representation Higgs fields, and further down to the Standard Model
(SM) via the D-brane splitting and Higgs mechanism. Also, we obtain three
families of the SM fermions, and have the left-handed and right-handed
three-family SM fermion unification in the $SU(12)_C\times SU(2)_L\times
SU(2)_R$ models, the left-handed three-family SM fermion unification in the
$SU(4)_C\times SU(6)_L\times SU(2)_R$ models, and the right-handed three-family
SM fermion unification in the $SU(4)_C\times SU(2)_L\times SU(6)_R$ models.
Moreover, the $SU(4)_C\times SU(6)_L\times SU(2)_R$ models and $SU(4)_C\times
SU(2)_L\times SU(6)_R$ models are related by the left and right gauge symmetry
exchanging, as well as a variation of type II T-duality. Furthermore, the
hidden sector contains $USp(n)$ branes, which are parallel with the orientifold
planes or their $Z_2$ images and might break the supersymmetry via gaugino
condensations.
