Let $Γ$ be a countable abelian group, let $k\geq 1$, and let $\mathrm{X}=(X,\mathcal{X},μ,T)$ be an ergodic $Γ$-system of order $k$ in the sense of Host--Kra--Ziegler. The $Γ$-system $\mathrm{X}$ is said to be totally disconnected if all its structure groups are totally disconnected. We show that any totally disconnected $Γ$-system of order $k$ is a generalized factor of a $\mathbb{Z}^ω$-system with the structure of a Weyl system. As a consequence of this structure theorem, we show that totally disconnected $Γ$-systems of order $k$ are represented by translations on double cosets of nilpotent Polish groups. By a correspondence principle of two of us, we can use this representation to establish a (weak) inverse theorem for the $U^k$ Gowers uniformity norms on finite abelian groups of bounded torsion.