It would be good to know the location all the time on the map of the 4 pace partners. Should be very simple to have 4 circles with the A B C D.
This would allow people to head out and warm up first and then look at the map to work out where the pace partners are to then ride to meet up with the “Group Ride” or for after you have completed a race or workout and just looking for that casual bunchy ride.
Once you also join the pace partner it would be good if you had the option to then choose to follow same route as pace partner so you do not have to keep pressing the turns and allow it to be set and forget