The ReferenceUSA database contains detailed company descriptions, corporate family trees, management directories, and competitor information for more than 20 million U.S. businesses. ReferenceUSA enables users to conduct a custom search to help identify and compare companies. Custom search options include business type, geography, business size and ownership type. Create custom search for Geography: radius of a zipcode (02452 or 02492) and Business Type: Keywords/SIC/NAICS 446191 & 446110 OR by Major Industry Group: such as Drug Stores. View the summary report and also export the data into excel for further manipulation.
Further research the competitors through the databases on the Article Databases -- Keeping Current area and by accessing their websites.
Competitor Analysis -- Just a few links to get you started.