Distributed Simulation (DS) is widely recognized to provide a valuable support for systems engineering efforts. Various contributions have addressed the adoption of model transformation approaches to enable a more effective DS use, with specific application to the HLA (High Level Architecture) DS standard and the generation of HLA simulation code from SysML system models. This paper extends such contributions by proposing a model transformation approach for the automated generation of the Federation Object Model (FOM), which defines the shared data exchanged during the execution of an HLA DS. The paper specifically addresses the generation of modular FOMs, as introduced by HLA Evolved, the latest version of the HLA standard, and describes the use of the proposed approach as part of a tailored DS development process.