Adding fields to Phone Call activity form

In the Phone Call entity, the "to" attribute is of type partylist. Would like to be able to add 开发者_如何学运维the parent customer to the entity so it can be added to the form and views so when listing phone calls the activities can be grouped by parent customer.

Typically the phone call activity is created from a Marketing list not manually so this field would need to be populated automatically.

Using the Regarding field works unless your phone calls are generated from a campaign/quick campaign. Then the Campaign uses the regarding field instead.

Have you tried populating the Regarding (regardingobjectid) field for the phone call?