For creating a route plan for a group of agricultural working machine systems for working a territory, the machine systems include route planning data determination devices and they exchange data with each other and, based on exchanged route planning data, one shared route plan is created for the particular territory. For controlling a group of agricultural working machine systems while it works a territory, one shared route plan—which has been created accordingly—is used, and a route planning system is provided for creating a route plan for a group of agricultural working machine systems to be used to work a territory.