From your discription it sounds like your looking to create a mass mailer list of some sort? From what I know and what I have found, Outlook will not handle this in native form, but I have seen a product called “GoMail” mentioned in several posts that claim to be able to handle your needs. Of course there is still work involved in setting this up. Your going to need to create either a .csv or .txt file containing all pertinant information for all 1200 of your would-be contacts. Once you have accomplised that task, then GoMail will provide you with the tools to import that list into an Outlook DL. I’ve never used GoMail so my info is not first hand, but it does not seem to be very expensive and has had some decent reviews.
This is a start. Hope it helps answer your question.