We present an idea that we propose to solve intrinsically time-dependent problems: project the problem by removing the temporal dimension, solve this projected problem and construct a solution of the temporal problem whose projection is exactly the solution of the projected problem. We will apply this idea to a relocation problem in the form of a two flows problem (a flow of vehicles and a flow of goods) in which preemption of goods is allowed. Preemption of goods is the act of allowing goods to be unloaded by the vehicle transporting it in order to be picked up by another to continue its journey. This constraint, requiring the synchronization of vehicles to exchange goods, is increasingly used in autonomous and semi-autonomous logistics warehouses.