With "Hotseat Session" you can choose to drive two or more cars (or race in two). At this point, if I remember correctly, you should assign "how many laps" and so, GP4 will divide the race laps into parts, inserting a countdown to allow the second driver (or the others) to continue the race using another car . In practice, the race will be led in turns. It is clear that the more drivers are selected, the fewer laps there will be. We played like this, before putting PCs on the net. On the web, each driver drives the car throughout the race and not at times on the same computer.