  For relatively hyperbolic groups, we investigate conditions guaranteeing that
the subgroup generated by two relatively quasiconvex subgroups $Q_1$ and $Q_2$
is relatively quasiconvex and isomorphic to $Q_1 \ast_{Q_1 \cap Q_2} Q_2$. The
main theorem extends results for quasiconvex subgroups of word-hyperbolic
groups, and results for discrete subgroups of isometries of hyperbolic spaces.
