In W. R. Grace & Co., Dearborn Div. v. Mouyal, 262 Ga. 464, 465 (1) (422 SE2d 529) (1992), 262 Ga. at 467 (2), n. 3, our Supreme Court explained that a restrictive covenant prohibiting a former employee from rendering services to any client of the employer must contain a territorial restriction expressed in geographic terms because that restriction, which does not take into account whether the employee had a business relationship with that client or whether it was the client who solicited the former employee, is otherwise unreasonable and overbroad in its attempt to protect the employer's legitimate interest in keeping the employee from taking advantage of the goodwill generated during his employment with the employer to lure employer customers away. "Thus, under Mouyal, a prohibition against doing business with any of an employer's customers, whether or not a relationship existed between the customer and the former employee, is overbroad in the absence of a reasonable territorial restriction."