The proliferation of Bluetooth Low Energy (BLE) in diverse applications has led to a dense clustering of piconets in confined spaces. BLE operates within the congested 2.4GHz ISM band, shared by numerous short-range wireless protocols. Frequency hopping and Adaptive Frequency Hopping (AFH) mechanisms have been introduced in Bluetooth to reduce interference with other protocols in the same band. However, research shows these mechanisms are ineffective in reducing inter-piconet interferences. These studies have demonstrated the relationship between the number of piconets and the level of interference. In this paper, we investigate the relationship between the similarity of channel maps and the number of neighboring piconets in interference intensity. Then, we present a light and practical coordination framework to address this challenge. Our solution employs a BLE gateway to detect its surrounding piconet masters and computes a better channel map to reduce the impact of inter-piconet interferences. We also introduce the Isolated Channels (ICA) algorithm for channel allocation of neighboring piconets with controlled channel overlaps for BLE5. Simulation results show a 20 to 60% reduction of interference level in environments with high to moderate inter-piconet interferences. To the best of our knowledge, this is the first practical BLE5-compatible solution for mitigating the inter-piconet interference problem and does not require modifying the standard stack.