Confusion on adding units to MR2/multi family residential

[Prince Martinez]

I have looked into a multi family home in Dekalb County Ga. I was conservative in my deal analysis on this property. My main concern is being able to take the two largest units and essentially build a wall in the middle of each to create four separate units, and one remaining smaller unit untouched to be used by me as owner occupy. My main confusion is in being able to do so within the zoning and code ordinances. Here is the analysis and address. Wondering if anyone else has done something like this. I tried looking online but have had mixed information. My only other option would be to go to the county planning office and speak in person with someone.https://www.biggerpockets.com/analysis/rentals/7271e539-c563...