You got that wrong. Black people in Georgia, Mississippi, Northwest Florida and Alabama are going to have very similar cultures. As a matter of fact Mississippi and Alabama were heavily peopled by the people from South Carolina and Georgia.
I think what you actually mean is that the Black people in the Mid-South are going to be culturally different from Black people in the deep South. From what I have seen is that the people of Tennessee, North Carolina, Kentucky and Virginia have a lot of similarities; which stands to reason, because Tennessee and Kentucky were heavily peopled by North Carolina and Virginia residents.
AncestryDNA maintains genetic communities. My mother comes back to South Carolina. I come back to coastal North Carolina, which are the exact regions that my grandmother and her sister told us that our families are from. Additionally, DNA testing shows that maternal lines are Mende people from Sierra Leone; so this stuff is more accurate than people believe.
Personally I break it all into about three parts
Chesapeake
-Primary States: Virginia*, North Carolina
-Secondary States: Kentucky, Tennessee, West Virginia
Low Country
-Primary States: South Carolina*, Georgia
-Secondary States: Florida, North Carolina
Gulf Coast
-Primary States: Louisiana*, Mississippi, Alabama, Texas
-Secondary States: Arkansas, Tennessee
The star notates the epicenter.
The mid-south and border areas are where it gets tricky.
Like you could argue western Tennessee falls into the gulf, but eastern Tennessee would be different. Same with Florida.
Edit- I forgot to add Maryland as a primary Chesapeake state