Feature request: send BCC mails to Android address group recipients

When travelling I usually send mails to 100+ recipients, telling about my travel experiences.
Unfortunately within k9 I can’t enter a group name available in Android’s phonebook into the BCC address field to “pull” the addresses related to a group into it.
Within Android’s phonebook I can select a group name, click on “send mail”, click on “select all” and “send with k9”, but then all 100+ addresses show up exclusively in the “to” address field and I have no chance to cut and paste all of them into the BCC address field - which I want to use to avoid distributing all addresses to all recipients.
Is there a chance for you to add this feature?
Thanks for developing and providing k9! I’m using it since years.