  Given a $C^2$ family of vector fields $X_1,...,X_m$ which induces a
continuous Carnot-Carath\'eodory distance, we show that any absolute minimizer
of a supremal functional defined by a $C^2$ quasiconvex Hamiltonian $f(x, z,
p)$, allowing $z$-variable dependence, is a viscosity solution to the Aronsson
equation $-\langle X(f(x, u(x), Xu(x))), D_p f(x, u(x), Xu(x))\rangle = 0.$
