Micheal, I am doing research on the Benjamin Franklin Blackburn family. From my records Benjamin married Mary Hartley in 1819 in Nicholas Co,Ky. They had one son, Benjamin, before Mary died ??. Benjamin returned to Bracken co. Ky and in 1825 married Matilda Carroll. they returned to Nicholas Co. Ky and then later back to Bracken Co. Ky. and finally to Brown co. Ohio. Benjamin and Matilda had 8 children, one being a John A. Blackburn in 1840 in Brown Co. Indiana. So your thought on the brothers may be correct.
Do you have any info on possible children of Hugh and Martha??
Thanks for any help given.