Big clubs could possibly organise specific groups, but the problem all clubs find is that to do it requires people willing to take on the role. And it's not just one person, as you need several for each group so that there is always at least one organiser for each group at each session. Sadly these people are often hard to find, especially in smaller clubs where you might only have a core of 20 or 30 people that actually show to every session with another 30 or 40 floaters who come along when it suits them. Quite often a lot of people seem to expect the club committee to just step up and do the role, but that's not really fair on them as it's not what they signed up for.
People are also very time-presured these days - they only have limited running time and so if they're training for something specific it can be very important to them that they can make the most of all sessions they do with the club. In these circumstances it not really fair to ask them to potentially compromise their run in order to manage a group of people. A lot also depends on the mix of people you have. As a small club we're lucky to have a really good mix of runners, both in age and ability, many of whom have known each other for a long time. This makes the social aspect of the club very strong which helps immensely. We organise all our speed sessions so that by running loops or laps everybody is running together and no-one can be left behind, but until recently we still had difficulty accomodating runners who wanted to run over 9:30 minutes per mile for our Thursday 7 mile runs.Thankfully however we seem to have found a solution that seems to be working.
Edited: 25/02/2011 at 14:48