Considering a multivariate linear model $\boldsymbol{Y = XB + E}$, where $\boldsymbol{Y, X, B}$ and $\boldsymbol{E}$ have dimension $n \times m$, $n \times p$, $p \times m$ and $n \times m$, respectively.
I read in this page about outliers only in $\boldsymbol{Y}$, i.e. without considering $\boldsymbol{X}$.
However, I'd like to simulate outliers for $\boldsymbol{Y}$ considering the pair $(\boldsymbol{Y, X})$ to regression problem.