Have you tried it? Did it work? I have what I suspect is a similar need...

Here's a sample of what it does:

http://app.feeddigest.com/digest3/QZOXR26YTA.html

I added 3 herders (chutry, zombie, critters) and that apparently is the limit on sources per feed for the free version. The next level, for $12 a year, allows 12 sources - still not really enough for the herd (although if we trim out some of the folks who aren't really blogging anymore... but I'd rather not do that).

And then it jumps to $50 annually. Which seems steep for me for something I could probably figure out (eventually) how to do on my own.

So I dunno....