Quasi-isometric rigidity of a class of right-angled Coxeter groups

We establish quasi-isometric rigidity for a class of right-angled Coxeter groups. Let $\Gamma_1,\Gamma_2$ be joins of finite generalized thick $m$-gons with $m\geq 3$. We show that the corresponding right-angled Coxeter groups are quasi-isometric if and only if $\Gamma_1,\Gamma_2$ are isomorphic. We also give a construction of commensurable right-angled Coxeter groups.