We are about to launch two product pages plus a corporate website. The goal is to keep a blog in all of the sites, but here it comes the question about how to do it in a way we get everything unified but do not mess with Google's web crawlers.

We considered the following options:

• Putting a blog from which we retrieve two categories with custom CSS, so we have a blog that sub splits two category-dependent blogs; this way we can get the feeds and will point to it
• Putting two product blogs of which we retrieve their posts into a bigger, corporate blog
• Putting three independent blogs

Despite I was for the first option, so we only have to address our content from the product pages, I would sincerely like to hear your opinion. We are afraid duplicate content or strange link games may make us lose PageRank. How would you do it?