You are headed in the right direction. 3 brothers coem over from Scotland, Eli, Robert and James McMullen. ---This James McMullen was born in 1758 and married Sarah Minton in 1781. They had 6 children (one of hem being James McMullen Jr.)
---James McMullen Jr. was born 6 Mar 1788 and married Rebecca Fain, 21 Mar 1811. *James Jr.'s Older brother William married Rebecca's sister Lavinia Fain*. The families moved to Lowndew County, GA in 1827. James Jr. and Rebecca had 12 children (seven boys and five girls). These sons are now known as "The Seven McMullen Brothers of Pinellas County". They named one of the sons James Purramore McMullen. ---James Purramore was born 11 Jun 1823 and died 17 April 1895. He married Elizabeth Campbell, 16 Dec 1844. *His brother Daniel married Elizabeth's sister Margaret Ann Campbell*.
I Come from Danial's side of the family, but I will warn you.... There are ALOT more James/John further down :) There is a family reunion every 4th of July in Largo if you want all the info. And the Heritage Village in Pinellas County can give you alot too. I hope all this information helps.