An investment group led by TG Walnut Hills LLC purchased the 41 buildings at 4551 Hunter South Ridge Drive, 4645 Drummond Blvd. and 4141 Walnut Hills Drive for $17.1 million, or about $23,619 per unit. The sellers were a group of companies that included Brenton Court Associates LLC, Brenton East Associates LLC, Hunters Ridge Apartments LLC and Walnut Hills Associates.