Fascinating blog I stumbled upon last night -- Amish America. By far, this goes into the nuances and differences in Amish culture far better then any book or website I've browsed.
'The relationship between authority and responsibility is learned very early. Although the younger chldren must obey the older ones, the older children may not make arbitrary demands on the younger. The four-year-old is expected to hand over his toy to a younger child if he cries for it, but in the absence of the parents the younger one must obey the older.'
From the book Amish Society by John A. Hostetler quoted here. That system, however, would serve many of us well in many more situations other then just siblings.