GroupTrack in 840 does not plot all group riders on the map!
Map isn't default zoomed out to show all riders - instead zoomed in on the other rider only. This can't be by design - the whole point is to plot each group rider's location on the map. No mention of any fixes in 9.26 firmware notes.
Also, it seems even harder (compared to 830) to discern rider icons from background map data - be great if Garmin could tone down all the map detail so we can more clearly see the riders and their track history.