The obvious choice of arrow between two groupoids is a homomorphism (or functor). This works well enough until one wants to induce morphisms of groupoid C*-algebras. The problem that arises is that homomorphisms of groupoids would be covariant on the source and range fibres of the groupoid, but contravariant on the unit space, so a *-homomorphism of the C*-algebras would have to face both directions. Buneci and Stachura introduce a different morphism of groupoids by considering actions of groupoids on other groupoids. They show that such morphisms covariantly induce *-homomorphisms of the groupoid C*-algebras. Meyer and Zhu call these morphisms 'actors' and build a categorical framework around the category of groupoids with actors as morphisms. In this talk, I will define actors for étale (twists over) étale groupoids and show that any *-homomorphism between Cartan pairs which entwines all of the Cartan structure must come from an actor between the underlying groupoids. In this way an equivalence of categories is realised.