Thanks for the John Anderson info...My experience is that there were always two three and even more individuals in the same family with same name...cousins, Uncles, Aunts, grandparents, etc.
I look for cluster families to help me identify various sets of families who might share the same ancestor. For example: If I find Wilburn, French, Whitaker in very close proximity in one county or state and then find the same surnnames together in another location, this tells me that these families were most likely related.
Now about the Marshalls....well as a matter of fact, I do have some Marshalls allied with Wilburns who lived in Cumberland, co KY....And from my I can gather these families go back to Baltimore Co MD....c 1710.....I need to check to be certain of this....But there several Wilburn/Marshall marriages within the time frame that you referenced.
I do know that the Rosses in Ross Co OH, were the same Rosses who married into the Wilburn line....BUT into a different family of Wilburns...a family of cousins to those in Cumblerand, Ky...but unless I have my info wrong(always possible)these Wilburns would not be siblings.
MOre and more I am finding evidence that these families were far more connected than I ever considered.