Mail.app mail list reply address
While replying you can turn on the Reply-To header which will let you set this. You can do that by either going to the View menu and turning on Reply-To or you can do it right from within the message itself, which is easier.



Alternatively you can try changing the default preferences via the command line. Chances are the Mail defaults won't have a Reply-To header defined, but you can add the key-pair with this:

defaults write com.apple.mail UserHeaders '{"Reply-To" = "theemail@goes.here"; }' 


or 

defaults write com.apple.mail UserHeaders '{"Reply-To" = "theemail@goes.here"; "Bcc" = "another@address.here"; }' 


If that doesn't work and you're like me and want to reverse those changes to keep preferences clean, you can edit the .plist file and remove them. The .plist can be found at:

/Users/&lt;username&gt;/Library/Containers/com.apple.mail/Data/Library/Preferences/com.apple.mail


I haven't tested the command line approach, but it should work because I looked this up and used that approach on a work machine once.

Hope this helps!