$$ \begin{equation}\mathbf{J}_h =\begin{bmatrix}\mathbf{W}_1^\top \mathbf{R}_1 \mathbf{J}_1 & \mathbf{0} \\\mathbf{0} & \mathbf{W}_2^\top \mathbf{R}_2 \mathbf{J}_2\end{bmatrix}\end{equation} $$