Three blogs, three options tables, one posts table

I am attempting to consolidate all my blogs so that I can have one place that displays everything I post, and two other sites that will selectively display my posts/pages based on either category or page hierarchy, respectively.

I want to be able to maintain the look of each site separately, but I want to do all my post/page editing in one place.

I figured one way to do this is to have three separate installations of WordPress that all point to the same exact database, but each install would point to a different OPTIONS table.

I then planned on creating custom templates to pull posts/pages selectively.

Anybody know how I could accomplish this? Or how to do this in a different way than what I have thought up?

Thanks!