How does Email to Case Premium handle duplicate contact records?
You have duplicate contact records in your Salesforce Org and would like to control which ones Email to Case Premium looks at.
By default, Email to Case Premium looks at all Contacts in your Salesforce Org and assigns the first one it finds with a matching email address when creating a new case.
You can technically restrict what Contact Record Types Email to Case Premium will look at.
Here are the necessary steps:
1. Define separate record types for the duplicate contact records.
2. Update the Organization Wide Default sharing model on the Contact object to be Private.
3. For the Email to Case Premium context user (defined under Setup > Develop > Email Services > Email to Case Premium), update this user's profile to disable the "Modify All Data" and "View All Data" permissions under the System Permissions section. You may have to clone the standard System Admin profile to do this.
4. Within the Object Settings for this profile, only enable the Contact record type this user should be able to access.
5. Create a new public group for the Context User (specifically for sharing rule purposes in the next step).
6. Create a sharing rule on the Contact object to provide this public group with sufficient access to records matching that record type.
From there, the Email to Case Premium context user will only be able to access Contacts for case association of that particular record type.
That being said, this seems to be a duplicate contact problem more than anything else. They may want to look into an application such as Dupe Blocker to help clean up duplicate contacts that they don't