The login is based on the username of the customer? If in the portal (joomla, wordpres, etc...) the customer have the username "Pippo" it can access (into Blesta) to the account owned by "Pippo"?
If into Blesta the username "Pippo" is assigned to "Pamela Anderson" and in the other system the username "Pippo" is assigned to "Jenna Jameson"?
I'm wrong or Jenna Jameson has access to the account owned by Pamela Anderson?