Having a lot of data under your site it is normal, that you want to aggregate different RSS feeds. But always playing around with XSLT and modifying your masters could be annoying after a while.
So, here we go! Why don't you try out RSS Suit?
Please leave some response either by voting on the project, or with a comment in the forum. Thank You!
If you find any of my projects useful, please visit me at http://sites.google.com/site/rpcheck/umbraco