There's a drop down menu,say on Watopia, for the 5 routes, and you decide what you will ride if free riding so you will always turn at the right points. If someone starts late but the others are down as friends the they will appear top of list of riders on course and you click on their name and hey presto, you join them. Did it to breedon and gave him a right scare up box hill. He had to pedal harder
Be careful though because at the moment joining them after ride started means you won't be auto directed so just tuck in behind at junctions and choose the correct turn using keyboard. Even if you do take the wrong turn there is a key/button to reverse and then make the correct turn.