I'm searching for a particular content management plug-in.

I'm searching for a particular content management plug-in. I'm in the health solutions industry and consult with several hundred clients - each with a private blog with only their content. This method narrowly targets specific content library to a specific individuals. So... I have a library of messages (preferably a blog) and choose to selectively re-publish elements to specific blogs.
The operative principle is NOT to publish under-relevant content to my audience. The concept is single-casting, where each member of my audience gets a customized content stream explicitly tailored to their interest.
The issue I face daily is my library management - where I have standardized messages, like this one http://care.whnlive.com/marksircus/2013/11/15/stress-betaine-hcl/ that conveys a specific message to a specific user. I reuse these messages frequently - so managing them in a "source" blog, and inclusion by reference would make my administration vastly easier.
Do you know of any plug-ins that do this in a wordpress context ?
Thanks,
Mark Squibb