A Factorio mod to synchronize wagon filters.
Press Shift+E (configurable) when hovering a cargo wagon to show the GUI. Each cargo wagon can be assigned to a group. All cargo wagons belonging to a group can be updated at once.
As for now, I couldn't find an efficient way to synchronize wagons automatically when the player configures a filter. The synchronization must be manually triggered by pressing the 'Broadcast' button in the GUI.