W3TC purge nukes site

Hi,
I am using W3TC and loving it. when pages are cached the site runs beautifully.
My issue is with posting new posts (about 3-5 daily).

upon each new post, W3TC flushes the cache casing a massive load on the database as cache is rebuilt.

Is there is a way to tell W3 to no purge all pages on new posts and updates. Only the feed and main page should update, and other pages should be taken care of by garbage collection.

I’ve been suggested a CDN, but I don’t think it will help as the “text” is still being served from the blog so it wont help with the database overload.

how do I set this up?

thanks,
udi