Rialto is a textual language for modeling heterogeneous systems, where different computational models are represented by scheduling policies that manage concurrent activities in the system. Rialto has a formal semantics defined using structured operational rules, which allows for the application of formal verification techniques to programs in the language. We show that the B method is suitable for this purpose. We present a novel approach for translating the language into B, where we have specified the actual Rialto semantics as a program interpreter in B. Rialto programs can automatically be translated into B specifications and we can use this interpreter to animate and validate them.