Often I need to write a mail to a group of several addresses, which I have collected into an address list, but some of the addressees shouls only be CC'd. In this case I currently cannot use the address list, I have to add each address separately. After inserting the address list into a "To:" field, I would expect a context menu command "Expand to list members", which replaces the single field by a list of "To:" fields, containing all members. Then one could change individual members to "CC:" or "BCC:".