Model-Driven Engineering (MDE) proposes to modularize complex software-intensive systems using multiple models where each module serves a specific concern. These concerns of a system might be diverse and the use of multiple heterogeneous models often becomes inevitable. These models adhere to different paradigms and use distinct formalisms, which makes it hard to ensure consistency among them. Moreover, these models might contain certain concepts (at times overlapping) that are reused for building cross-concern views/models. Maintaining models using separation of concerns in a heterogeneous modeling space becomes difficult. Traditional MDE suggests the use of model transformations to maintain the mappings between heterogeneous models. In this paper, we introduce a different approach based on model federation to map heterogeneous models. In contrast to traditional approaches where heterogeneous models are gathered in a single technological space, model federation keeps them in their own technological spaces. We provide a mechanism so that elements of these models are accessible for the development of cross-concern views/models from their respective technological spaces.