How do I search for 2 foster kids adopted from fostercare in GA in 1976?

My aunt, who is in her 90's and lives in Griffin, GA, was a foster parent in the mid 70's for 2 children, Bobby and Lucy. They were adopted out of their (her husband is now deceased) foster care in 1976. She believes they were adopted by a dentist from the state of Georgia in 1976. She so loved these 2 kids and was heartbroken at the time because the state would not let her have any contact or knowledge about their whereabouts. She has said so many times she wishes she could find out how they are. Bobby stayed with her for 2 years and was 4 when he was adopted in 1976. He'd be in his mid 30's today. Lucy (Bobby's sister) stayed with her for 1 year and was adopted at age 7. Lucy would be 40ish. The two of them, brother and sister, were both adopted by the same family, presumably a dentist in Georgia, in 1976. I have no clue how to help my aunt find these two people, but she would so love to find them. Does anyone have suggestions for me to help me locate them?