  We present a scheme to construct grand unified models based on the
superconformal algebra and the inclusion of matter fields in the adjoint
representation of supersymmetry. As an illustration, we implemented the
Georgi-Glashow $SU(5)$ model. The model predics the existence of a hidden
$(\mathbf{1},\mathbf{24},0) + (\mathbf{5},\mathbf{5}^\ast,-y') +
(\mathbf{5}^\ast,\mathbf{5},y')$ sector and an anomalous $U(1)_Z$.
