Database website for members of multiple sites

We need a website which is used by individual sites around the country with there own unique login to add members and update member details, there needs to be separate logins only displaying relevant information for retailers to then check an individual members details and that his details are currently valid. So Members= the person on the database the customer Site= enter the members details on the database and confirm they are correct also entering start date for member to which it expires 365 days after this date then showing inactive or expired( needs a way of simply renewing. Shop= doesn't enter details but needs to type in the members unique number it then needs to show if the member is active or current, the members full dame D.O.B and Postcode All needs to be highly secured due to data protection.