Use the blog "archived" for a blog archive

Hi,

i think about using archived blogs. On my site i have a lot of short blogs, there are only new entries while a conference or event. after this i like to close the blog. Close means no more writing (no comments maybe) but they had to be visible for visitors.
The blog "archived"-flag make blogs invisible for user but let the posts in db. But it must be a way to fix this function a little bit to make the blog visible again.
and if it works there must be a way to list all blogs wich are archived and these wich are not archived. In the moment i use the list-blogs-widget for my navigation. bu i like to make 2 lists, one with archived blogs one with new blogs.

Any hints where to find it?

greetings staudi

Edit: or easier put anything in the "list blogs widget" that blogs with now new entry after 2 weeks will not be shown with a parameter in the function... hm... i think i have to have a look... (o: