In this article, we present a decentralized control scheme for regulating input-affine nonlinear interconnected systems. In particular, we propose a codesign strategy to synthesize a control policy and an event-triggering threshold at each subsystem of an interconnected system to simultaneously optimize the subsystem performance and reduce the computational burden on the controllers by enforcing aperiodic dynamic feedback. To this end, we formulate a differential game at every subsystem to design a decentralized control scheme in which we treat the control policy as the minimizing player and model the effect of interconnection inputs and the error introduced due to aperiodic feedback as a team of adversarial players. We then employ the solution to the proposed game for designing both the control policy and the event-triggering threshold at each subsystem. With the proposed approach, we also derive the conditions that guarantee the input-to-state stability of the overall system by leveraging the well-known small-gain theorem. Moreover, we show that these conditions, expressed in terms of the attenuation constants and penalty matrices introduced in the formulated game, are obtained as linear inequalities even when the dynamics of the subsystems are nonlinear. Finally, we illustrate the applicability of the proposed scheme to regulate interconnected systems using numerical examples.