Members of the OpenSwarm consortium have created a novel minimal-overlap (MO) centrality metric for gateway designation in low-power real-time wireless sensor networks (WSNs) operating under the time-synchronized channel hopping (TSCH) mode. The MO metric quantifies how much routing paths of active data flows overlap when directed to a candidate gateway—higher overlaps imply more contention and reduced schedulability. By selecting gateways that minimize this overlap at design time, the proposed approach improves real-time performance without requiring additional infrastructure. The method supports both single- and multiple-gateway designation by applying MO centrality globally or within network clusters, respectively. Simulation results under earliest-deadline-first (EDF) scheduling and shortest-path routing show that our method significantly outperforms classical centrality-based strategies (eigenvector, closeness, betweenness, degree), improving schedulability by up to 40%, and enabling over 2x more schedulable flows compared to worst-case gateway designation.