The current standard Customers V3 entity would as part of the target field mappings only include the information that should be reflected as Primary contact details with reference to the type. 

Customer X would have two email addresses. 1 to many relation. 

Email 1 - Customer X - Primary

Email description = Test Email 1

Contact Email = Test1@scania.com

Contact Email purpose = Invoice

Primary contact email is IM = Yes

Email 2 - Customer X - Secondary

Email description = Test Email 2

Contact Email = Test2@scania.com

Contact Email purpose = Business

Primary contact email is IM = No

The standard Customers V3 entity would only provide the following fields as part of import/export based on the information above: 

1. PRIMARYCONTACTEMAILDESCRIPTION

2. PRIMARYCONTACTEMAIL

3. PRIMARYCONTACTEMAILPURPOSE

4. PRIMARYCONTACTEMAILISIM

We would need to ensure that this entity could consume the information about multiple email addresses, phone numbers, URL´s, FAX numbers etc with reference to the type and the different purposes. This is valid when we have a one to many relation between the customer and the same type (email, phone, url, telefax, fax, twitter, facebook, linkedIn). To avoid customizations, it would be good to have a separate entity for the Customer/vendor contact details.

If that would be available, there would be options to add relations between the individual entities, create relationships between staging tables and setup metadata for DMFEntity and refresh the entity list for running projects based on mappings already in place.