I believe that the Hiram you are looking for is the son of Angus Alexander and Unity Murphy of York,SC (see refer to lds site www.familysearch.org).My Hiram, born abt 1804, is the same as yours.I didn't know name of first 2 wives, but can confirm death info, and Martha Tinsley marraige.How do you know Hiram was born on York,SC? My last census puts him in Union,SC. Please let me know any details and I will keep you advised of what I find out. I am looking for a will etc. that will positively tie them together.Good luck!!