To provide each affiliate and the national nonprofit the ability to see only its own donor data in a single Salesforce org, the consultant should use Criteria-based Sharing. Here's why:
Criteria-based Sharing:
This feature allows for defining sharing rules based on specific criteria, such as record ownership or certain field values.
By setting up criteria-based sharing rules, each affiliate and the national nonprofit can be restricted to viewing only the records that meet the specified criteria, such as records tagged with their specific region or affiliate identifier.
Reference:
Salesforce Sharing and Visibility Guide
Salesforce Criteria-based Sharing Rules Documentation