In Thurman v. State Farm Mut. Auto. Ins. Co., 278 Ga. 162 (598 SE2d 448) (2004), Gail Thurman, a United States Postal Service ("USPS") postal carrier, was injured when a vehicle driven by Mamie Brown struck her postal truck. Thurman received medical and income benefits from USPS's workers' compensation and group medical insurance carriers. Thurman and her husband later sued Brown and settled with Brown's liability insurance carrier for approximately $ 96,000. USPS's insurance carriers asserted subrogation rights from the proceeds of the settlement, so the Thurmans ultimately received only about $ 61,000. They then sued their UM carrier, State Farm Mutual Automobile Insurance Company, arguing that Brown was underinsured because their $ 75,000 UM policy exceeded the net proceeds of their settlement with Brown's liability carrier. The trial court awarded summary judgment to State Farm and we affirmed. See Thurman v. State Farm Mut. Auto. Ins. Co., 260 Ga. App. 338 (579 SE2d 746) (2003).