A multi-FPGA system, Flow-in-Cloud (FiC) system is currently being developed as a server for Multi-access Edge Computing (MEC), one of the core technologies of 5G. FiC system is composed of mid-range FPGAs directly connected by highspeed serial links and works virtually as a single FPGA with huge resources. Since the applications of MEC are sometimes timing- critical, a Static Time Division Multiplexing (STDM) network has been built on the FiC system. However, the STDM network suffers from the extended latency and low usage of the network resource especially when the network traffic is light. Here, we propose a hybrid router that allows packet switching to use empty slots of the STDM. The evaluation results from a real system appear that packet switching is 2.42 times faster than STDM with 8 boards FFT. Also, we propose and evaluate a dynamic allocation method that changes the switching mode according to the network load.