Help on automatic emails

Can anyone recommend how I can do the following:
1. I need to send out newsletters to more 1 million users, track their click response, have that integrated into my customer information backend system, have cycles of newsletter, have sub-groups of customers who get different newsletters based on when they joined or what and when they purchased, or when they last logged in and that type of thing
2. I need automatic emails sent out when people join and buy and things like that.
3. Big mail outs can never interfere with my personal mail or the automatic mailouts, particularly emails with passwords and that kind of thing.
4. The mail must come from one server with SPF records so that it's not identified as SPAM

At the moment, we're using an inhouse developed system. I'm thinking maybe we just set up a separate mail server and modify our exisiting system.

Is it possible to have SPF records on more than one server and maybe split the company email from the newsletter emails?