I have a problem on how to add field like dropdown in newsletter queue label as "GROUP" this label has an option "Customer" and "Guest". My questions are how can i add dropdown and how to code the function and what are the files and modules that i use? For example: I have 2 subjects "Test newsletter" and "Test newsletter 1". Those subjects has corresponding "Groups" to choose. "Test Newsletter" has group "Customer" then another one is "Guest". When i send to the subscribers "Test newsletter" all the subscribers under "Customer" will recieve that kind of letter while the other one will recieve "Guest" group.