  We present a four-parameter family of ordinary differential systems in
dimension three with affine Weyl group symmetry of type $D_4^{(1)}$. By
obtaining its first integral, we can reduce this system to the second-order
non-linear ordinary differential equations of Painlev\'e type. We also study
this system restricted its parameters. Each system can be obtained by
connecting some invariant divisors in the system of type $D_4^{(1)}$. Each
system admits affine Weyl group symmetry of types
$B_3^{(1)},G_2^{(1)},D_3^{(2)}$ and $A_2^{(2)}$, respectively. These
symmetries, holomorphy conditions and invariant divisors are new.
