Arthur Lydiard said in some of his books, starting in the 60s, that group training was vital to success. The reason being that there is a constant source of motivation because the slower runners see the faster ones and want to get to that level and they can see how much work it takes to get there. For the faster runners, they are forced to continue to work hard or someone will take their place and as one of the examples on the team they have a responsibility to do things right. The Hansons started a group of marathoners in 1999 with group training as one of the focuses. They have had success but they have mostly recruited the blue collar D3 and slower D1 athletes instead of the blue chip NCAA winning athletes. My friend suggested that perhaps Nike was offering many of these athletes two different contracts: stay where you are we'll keep paying or come here and work with the best and we'll make it worth your time. Wether or not that is happening the important thing is that Nike is offering on site help and a great support system to some of the best athletes in the country.
For more information. Read that every day.