Post to multiple WP blogs from main blog

I have about 30 stand alone self hosted wp blogs covering many inportant niches. I want to post from my main wp blog and send that post to other selected blogs that fit that topic. I haven't used Multipress before because I've been vague about it's uses. Ditto BuddyPress. I lost my main blog with 400,000 comments recently because of hacking so am rebuilding. What is best plugin for hacking? I am affiliate for Clickbank, Amazon, JVZoo, RAPbank + others. Would like to add more plugins eg for client advertising but it all takes time but will add Comment Spam soon. Do I have to add selected wpmu plugins one by one to all my blogs or is there an easy way to save labour and time? I cannot praise your website enough! You guys are gold!
Thanks Kevin Johnston
Paid member: User=IMwinner
email=giddaymate@hotmail.com.au OR kelvatim1@westnet.com.au