When sending emails from Dynamics CRM, we want to send e-mails to only accounts and contacts. However, the built-in e-mail activity entity allows for users and leads to be added to the recipients as well.
According to Dynamics CRM Activity Parties, there are 12 types of activity parties. The ToRecipient type "specifies the recipient in the To field" and you can select Account, Contact, Lead and User. On the same page, there is a Customer party type from where you can select only Account and Contact.
According to Activity Party Entity, the Customer party list is not available as a party list for the e-mail entity. We'd prefer to use the built-in e-mail entity instead of customizing our own, so it seems to me that the remaining option is to limit the ToRecipient party list to Accounts and Contacts. Can this be done, and have I missed other ways to get around this issue?