I question the wisdom of this.... when I was a young teenager I was nearly run over by an 18 wheeler. I was riding with my parents. We were on a country road with a small shoulder. I was somewhat ahead of my parents. Said 18 wheeler pulls out and goes around my parents - does not look ahead to see me, pulls back in, also overcorrecting some to the right, putting him on a course to cream me. Something - don't know what, intuition? eyes in the back of my head? the sound of an 18 wheeler coming to destroy me? made me go off the road and into the grass. Saved my life.
I've noticed too many times where a driver does this - pulls around one cyclist, but then isn't looking for the one up the road a little. Unless you are very spread out - so there is a lot of room for the driver to pull in and drive some distance before he/she needs to pass again I think it may be better to stay together. Then at least the motorist has fewer choices about passing, even if it may be a little frustrating for him/her.