This work presents a novel approach for analyzing and controlling bearing rigidity in multi-robot networks with dynamic topology. By decomposing the system's framework into subframeworks, we express bearing rigidity, a global property, as a set of local properties, with rigidity eigenvalues serving as natural local rigidity metrics. We propose a decentralized, scalable, gradient-based controller that uses only bearing measurements to execute mission-specific commands. The controller preserves bearing rigidity by maintaining rigidity eigenvalues above a threshold, and also avoids inter-robot collisions. Simulations confirm the scheme's effectiveness, with information exchange confined to subframeworks, underscoring its scalability and practicality.