To support military operations effectively, modern tactical networks need to manage increasingly large amounts of data and ensure that relevant information reaches the intended consumers within actionable times and under constrained resource availability. Solutions based on distributed Information Management Systems (IMS), which have been adopted to control the complexity of data sharing and security requirements, are often paired with traffic management, e.g., policies configured on network routers, and software-defined networking (SDN) to provision Quality of Service (QoS) to data flows competing for the available bandwidth. Nonetheless, the need for centralized control and administration is in contrast with the nature of tactical networks, especially in presence of multi-national coalition operations. To address these concerns, we present an architecture and API for IMS that enables network-aware traffic shaping at the IMS level, which can work in concert with other traffic management solutions or by itself. Additionally, we discuss a traffic shaping algorithm that operates uniquely at the application layer within the IMS and prevents network congestion, while ensuring that the desired QoS is met even in presence of dynamic network conditions. Finally, we demonstrate the efficacy of the proposed architecture via experimental evaluation of an implementation of such architecture over an emulated tactical network.