Share one taxonomy across multiple blogs in 3.0 [duplicate]

Possible Duplicate:
WordPress Multisite – global categories

I have a series of blogs that will use some, but not all, of the same posts. We have one blog where many of the posts are written, and then shared down to the other blogs, based on topic. We cannot accomplish this properly using categories, though we’ve thought of that.

All the blogs use the same theme, the theme changes slightly based on the blog. I would like to do something like this:

register_taxonomy(
    'some_categories',
    array('post'),
    array ('hierarchical' => true,
    'label' => __('Some Awesome Categories'),
    'singular_label' => __('Some Awesome Category'),
    'query_var' => 'some_categories')
    );

We’re using a path install so if I got to http://domain.com/blog1/wp-admin/ and add some categories, they do not show up at http://domain.com/blog2/wp-admin/.

Is this possible? I know that WP 3.0 has a different set of tables for each blog, so this may not be possible.

TIA

My recommendation would be to place the code that defines your custom taxonomies into a plug-in and activate the plug-in site wide. This will cause the new taxonomies to become active on all the sites in your network.