I administer several computers that have Thunderbird installed. I know Thunderbird has an option to require all email to be encrypted. However, I would like a way to allow unencrypted email normally, but require encrypted email to certain contacts.
For example, if I email firstname.lastname@example.org, Thunderbird should require encryption, but if I email JohnDoe@othercompany.com Thunderbird would allow unencrypted emails.
Are there any settings or Add-ons that would give this functionality?