Here are some of the records described in the GA State Archives:
Ordinary/Superior Court Records.
[Please note: Many of these records are found in either the Ordinary
(Probate) Court or the Superior Court, depending on the county.]
Apprenticeship/Indenture Registers, 1800-1930: These records primarily
document freedmen, but also document whites. Available for 34
counties: Baldwin, Campbell, Carroll, Chatham, Chattooga, Cherokee,
Clay, Clinch, Coweta, Dooly, Glascock, Haralson, Jackson, Laurens,
Liberty, Lincoln, Madison, McDuffie, Meriwether, Mitchell, Monroe,
Morgan, Oglethorpe, Polk, Pulaski, Putnam, Sumter, Taliaferro,
Terrell, Thomas, Washington, Webster, Whitfield, and Wilkes.
Free Persons of Color Registers, 1780-1865: Registers usually include
name, age, occupation (sometimes), property, and white sponsor.
Available for 21 counties: Appling, Baldwin, Camden, Chatham, Clarke,
Columbia, Elbert, Emanuel, Hancock, Jefferson, Jones, Liberty,
Lincoln, Lumpkin, Morgan, Pulaski, Richmond, Screven, Taliaferro,
Thomas, Warren, and Wilkes.
There might also be Freedmen's bank records that could possibly have a
sponsor mentioned. Depending on when Ritter died, her children's names
may need to be looked up instead in order to find some link or record
tying these Dorseys to a white family. If there were no other Dorseys
in the vicinity (white Dorseys), it could make record searching more
difficult. If all of her children were also formerly owned by a white,
I would think that to free them all at once would be a pretty big
deal, so she could have been free since she was much younger. Did
government officials need to officiate over the freeing of slaves, or
at least make some note of it during assembly proceedings? I would
think it might be difficult for a former slave to move around at that
time period due to fears of being taken back into slavery by others
disregarding their free papers. So there is probably a pretty good
chance that Ritter Dorsey didn't move far from where she was living if
she was with a white family, and that all the neighbors knew that she
was free and knew her "sponsor" family.
Sounds like a great quest with lots of possibilities to hunt down.