  In this paper we study a multi-species disordered model on the Nishimori
line. The typical properties of this line, a set of identities and inequalities
among correlation functions, allow us to prove the replica symmetry i.e. the
concentration of the order parameter. When the interaction structure is
elliptic we rigorously compute the exact solution of the model in terms of a
finite dimensional variational principle and we study its properties.
