View and control the "from" address when sending emails from OtherInbox

I would like to be able to see which domain I used for any given mailbox. The "to" field currently just truncates to the mailbox name, but I have multiple domains. Also, this gets harder with the new filtering flag for yahoo groups. This matters because, when replying or composing an email to a group, I need to make sure the "from" address that I use matches the one that is subscribed to the group. At least for yahoo groups, that is a requirement for sending email to the group.