  Using a six-orientifold, fourbranes and four fivebranes in type IIA string
theory we construct $\mathcal{N}$=1 supersymmetric gauge theories in four
dimensions with product group $SU(M)\times SO(N)$ or $SU(M)\times Sp(2N)$, a
bifundamental flavor and quarks. We obtain the Seiberg dual for these theories
and rederive it via branes. To obtain the complete dual group via branes we
have to add semi-infinite fourbranes. We propose that the theory derived from
branes has a meson deformation switched on. This deformation implies higgsing
in the dual theory. The addition of the semi-infinite fourbranes compensates
this effect.
