  Given groupoids $G$ and $H$ and a $(G,H)$-equivalence $X$ we may form the
transformation groupoid $G\ltimes X\rtimes H$. Given a separable groupoid
dynamical system $(A,G\ltimes X\rtimes H,\omega)$ we may restrict $\omega$ to
an action of $G\ltimes X$ on $A$ and form the crossed product $A\rtimes
G\ltimes X$. We show that there is an action of $H$ on $A\rtimes G\ltimes X$
and that the iterated crossed product $(A\rtimes G\ltimes X)\rtimes H$ is
naturally isomorphic to the crossed product $A\rtimes (G\ltimes X\rtimes H)$.
