I use GNUs for most of my email needs, but also have notmuch for rapid search of my inbox. Trouble is, when I choose a message in that notmuch search, it doesn’t open it with gnus but with its own message-mode spinoff called Message[Notmuch]. In GNUS I have an automatically added BCC address (my “sent-mail” inbox, which is downloaded across devices to sync what I’ve sent). How can I get the same automatic BCC added to anything I send in reply with Message[Notmuch]?