I'm looking for something like that. I have got 1 gmail-account, it's a collection, tag, and archiving account, say MyArchive@gmail.com. And I got 5 active Email adresses that I forward EVERYTHING from to MyArchive@gmail.com , there are no copies of these EMaily anywhere but on MyArchive@gmail.com .
That is called 'email spoofing' and is generally considered spam. This happens because the sending smtp server and the from address don't match. TB! has the ability to provide this facility and does it well, but your approach is to disarm its strength. To achieve the ability to see all in one inbox and reply separately to each, I suggest you create an account for each email id and then set up virtual folders for inbox and sent folders. Works beautifully and transparently. I think you will like it. I have multiple email accounts and they all appear in one inbox. Good luck.
That's not what I explained. If you 1) stop forwarding to myarchive@, 2) set up accounts for each in TB!, 3) set up virtual folder for inbox, then whenever you receive mail into the virtual folder, your reply will automatically use the correct responding email id. This eliminates the need for myarchive@ account. I understand the intent, but letting TB! do the heavy lifting will give you exactly what you want: one inbox and automatically use the appropriate email id for responding.
David's suggestion sounds like a very good and simple solution.
Note that in The Bat, when you respond to a message, you can manually choose a different 'From' account quite easily - just click on the account name in the status bar below the editor. Maybe you can also choose a different 'From' account automatically through a macro in the template, I've never tried that.
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