The echelon is probably not going to be useful for a handful of riders, but the single paceline gives real advantages into the wind and in pulling along a group. It is easy to go too fast for all the members of the group. The idea is to bring the group in together–not to see who is strongest.
Some good pace line etiquette here–Corrie
Ideally, a group should contain both novices and experienced riders who don’t feel compelled to prove themselves on every ride. The key is riding safely and effectively in a paceline