  In two papers published in 1979, R. Bowen and R. Bowen and C. Series
introduced a dynamical system from a Fuchsian group, acting on the hyperbolic
plane $\mathbb{H}^2$. The dynamics is a map on $S^1$ which is, in particular,
an expanding piecewise homeomorphism of the circle. In this paper we consider a
reverse question: which dynamical conditions for an expanding piecewise
homeomorphism of $S^1$ are sufficient for the map to be a ``Bowen-Series-type"
map (see below) for some group $G$ and which groups can occur? We give a
partial answer to these questions.
