The leader should ensure that all the party is in sight and if necessary, stop or slow down to allow everyone to catch up.  He or she should keep in contact with the back marker, who should tell the leader if someone has difficulty keeping up.   The party should take a short break in such situations and not set off as soon as the back marker arrives.  This applies especially after steep climbs.  The leader will also arrange a lunch stop.  It is usually not appropriate for walkers to get ahead of the leader as they may go in the wrong direction.