  In a stable theory, a stationary type $q \in S(A)$ internal to a family of
partial types $\mathcal{P}$ over $A$ gives rise to a type-definable group,
called its binding group. This group is isomorphic to the group
$\mathrm{Aut}(q/\mathcal{P},A)$ of permutations of the set of realizations of
$q$, induced by automorphisms of the monster model, fixing $\mathcal{P} \cup A$
pointwise. In this paper, we investigate families of internal types varying
uniformly, what we will call relative internality. We prove that the binding
groups also vary uniformly, and are the isotropy groups of a natural
type-definable groupoid (and even more). We then investigate how properties of
this groupoid are related to properties of the type. In particular, we obtain
internality criteria for certain 2-analysable types, and a sufficient condition
for a type to preserve internality.
