One blog or two blogs

I was hoping to get advice on how to set up a site for a client. It’s two institutions who co-blog (one writes a post ever other day).

So the landing page will have three columns. The first two listing recent posts by each institution and the third lists general info (search, links, rss feed, about…etc)

You can then view posts by each individual institution. And when viewing these posts the first column will then list categories, monthly archives, institution authors.

I was curious if this could be done with one installation of wordpress or if it would need to be done with two.

I figure if I had one installation, each institution would be a category, and that is how someone could view all posts by one institution. However, the column that lists the authors and categories… Is there a way to filter that (i couldn’t find it in the documentation)? For instance, only give me authors who have posted in category ‘x’? Or give me categories that are also tied with category ‘institution x’?

The other way would be to have two installations of WordPress running and have an index page that I manually create to pull their latest 10 entries or so. The issue here is the ‘search’ field. I don’t believe it’s possible to search across multiple wordpress installations, is it?

Any tips or suggestions? I’d really appreciate it.

Thanks!