Magento Open Source, 1.9.x
Customer Account Scope

The scope of customer accounts can be limited to the website where the account was created, or shared with all websites and stores in the store hierarchy.

To set the scope of customer accounts:

1. On the Admin menu, select System > Configuration.
2. In the panel on the left, under Customers, select Customer Configuration.
3. Click to expand the Account Sharing Options section.
4. Set Share Customer Accounts to one of the following:
  • Global

    To share customer account information with every website and store in the Magento installation.

    Per Website

    To limit customer account information to the website where the account was created.

5. When complete, click the Save Config button.