Are suffixes like Jr. and Sr. ever used to distinguish e.g. grandson and grandfather? The most common Junior and Senior combinations are father and son, but what about in other contexts, such as grandson and grandfather (assuming that they have the same name)?

Conventional wisdom is that Junior and Senior are used to distinguish a younger from an older person of the same name. Further, it is said that the two need not be related in any fashion. I don't remember seeing an unrelated pair myself, but that's what is said.