The Functional Mock-up Interface (FMI) has matured in co-simulation and data exchange for continuous-time systems; however, it still lacks sufficient support for event handling, especially for external events. Most existing master algorithms lack a unified modeling and processing mechanism for external events, which limits the application of the FMI standard in discrete event-driven systems. To address these issues, we first construct an external discrete event model based on the Discrete Event System Specification (DEVS) and propose a method for external event localization and handling within the FMI framework. On this basis, we extend the co-simulation master algorithm to support hybrid co-simulation involving external events. Experimental results demonstrate that the proposed method supports dynamic structural models and shows high accuracy and adaptability in external event simulation.