The country’s largest pharmacy benefits manager, Express Scripts, is considering creating a network of outlets that do not sell tobacco or alcohol, The Wall Street Journal reports.

Last month, Caremark, the pharmacy benefits management arm of CVS, announced it will require some customers to make a $15 co-payment on prescriptions filled at non-CVS pharmacies that sell tobacco products. The rules will encourage customers to fill prescriptions at CVS-owned pharmacies. They will also put financial pressure on other pharmacies that are part of the Caremark network to stop selling tobacco products.

Express Scripts is surveying pharmacy owners about creating a “no-sin network.” The company has not yet made a decision on whether to go ahead with the plan, or whether costumers would be charged extra co-payments if they visit a pharmacy that sells tobacco or alcohol, the article notes.

CVS stopped selling tobacco products in September. Experts say their main rivals, Walgreens and Rite Aid, are unlikely to follow the company’s lead.