Stature and separability in graphs of groups

We introduce the notion of finite stature of a family $\{H_i\}$ of subgroups of a group $G$. We investigate the separability of subgroups of a group $G$ that splits as a graph of hyperbolic special groups with quasiconvex edge groups. We prove that when the vertex groups of $G$ have finite stature, then quasiconvex subgroups of the vertex groups of $G$ are separable in $G$. We present some partial results in a relatively hyperbolic framework.