The number 4-5 runner's (so a varsity scorer) best friend joined cross country this year. The problem is that the best friend is not very fast, and a lower end JV runner. However, the good runner doesn't want to "leave them behind" etc. (they wouldn't really have anyone to run with then, because of different paces etc) and so slows down a lot on some runs. I have tried getting the #1-3 runners (who usually run together, or sometimes #1 runs alone and 2-3 run together) to get the runner to run with them... but runner #4-5 claims they are "too fast" sometimes (which isn't really that true) and doesn't have anyone else to run with really so just runs with their friend.
How can I stop this from happening or get runner #4-5 to run faster? They are a lot faster than their friend, so they should be doing runs faster in general (the occasional recovery day is okay I suppose).