My b2evolution Version: 2.x or 3.x

I'm really trying to maximize the organizational power of b2 by actually using categories instead of just using multiple blogs "as sections", but there's one thing that makes me turn back. I'm trying to make it so that when when somebody is looking in the "videos" category, for instance, the links in the sidebar widget are all video posts, and so on for other categories. WIth multiple blogs and post lists, this is easy to achieve. Is there a way to get post list/links for a just single category in the sidebar? I see in 3.x you can order items by category, but I assume that all categories will be displayed one after the next.

The ideal solution I think would be that when setting the display/filter perameters in a stub file, such as would filter the blog to a category, it also filtered the post list widget on the side. :/

[url=http://mostmodernist.com/]my website[/url] is the example.

I'm building another, which needs more nuanced organization. I'd like to use categories so that I can take advantage of display perameters for organizing data, but organizing the content does me no good if I can't organize the navigation.

I feel I must be missing the easy and obvious solution. COME OOOON EASY ANSWER!