"each other" or "one another?"

My sis is editing a book for a friend of hers, and they are having a debate over which is right, as in "They stood next to.."

He claims he was taught in school that "each other" means two people, and "one another" refers to three or more. I must confess, I've never heard of such a thing.

What do you think?



Rowdymama is only Catty in disguise. For some reason, couldn't log in as Catty, so had to re-register.