Does Not allow Mailing List in CC

When sending Invoices to customers I check Send to Customer and it includes the customer ID, automatically to the “To” list. However if i include a mailing list to “cc” to myself, it adds it in the “To list” and not in the “CC”. This is a good feature but it would be a significantly enhanced feature if we have an option to choose whether “ mailing list” should appear in “to” or “cc”