>>1925261If they overtake you and you can keep up go for it but keep a bit of distance (1 wheel at least) to not worry the guy who doesn't know you. Would be nice to do a bit of small talk while you are there on the rear " hi guys were are you goin to? Mind if I join the train for a bit etc."
If you instead reach a slow group why even bother, politely overtake them and go on your merry way.