To configure a unified database for three websites without seamless login between the sites, you should use:
* One site group with SSO disabled and one segment:
* Creating one site group ensures that all websites share the same database.
* Disabling Single Sign-On (SSO) ensures that users do not automatically log in across the different websites.
This configuration maintains a unified data store while keeping the user sessions separate.
References
* SAP Customer Data Cloud Site Groups Documentation

To ensure that only users who have granted consent are exported to an SFTP server using dataflows, you should use thedatasource.read.gigya.accountcomponent with the consent parameter.
* Using datasource.read.gigya.account with consent parameter:
* This component reads account data from SAP Customer Data Cloud.
* By specifying theconsentparameter, you can filter the accounts to only include those where users have given consent.
This approach ensures that only data from consenting users is included in the export.
References
* SAP Customer Data Cloud Dataflows Documentation