My guesses:
1-6A - Tupelo, Southaven, Desoto, Horn Lake, Oxford, South Panola, Hernando, Columbus
2-6A - Madison, Clinton, Murrah, Starkville, Greenville, Warren Central, NW Rankin, Provine
3-6A - Oak Grove, Brandon, Meridian, Petal, Terry, Jim Hill, Pearl, George Co?
4-6A - Ocean Springs, Harrison, Biloxi, Gulfport, St. Martin, d-Iberville, Hancock, Goula
1-5A - Olive Branch, Lewisburg, Center Hill, Saltillo, Lake Cormorant, Cleveland, West Point, Lafayette
2-5A - Grenada, Germantown, Callaway, Vicksburg, Neshoba, Ridgeland, Canton, Holmes Co.
3-5A - Forest Hill, Natchez, Wayne Co., West Jones, Laurel, Brookhaven, North Pike, Wingfield
4-5A - South Jones, West Harrison, Hattiesburg, Long Beach, Picayune, PR Central, Gautier, Stone