My situation is that I am using global-search with post-indexer and and am using the mu plugin sitewide-tags to push sub-blog posts to the main blog.It works great although it does duplicate the sub-blog post in the main-blog, its fine because the permalink links back to the the sub-blog post - I applied a filter to restrict the main-blog version of that post not to show in the main blog loop. Awesome, because the SE then doesn't get presented duplicate content. I applied this code below at line 175 to the post-indexer to avoid any posts being indexed from the main blog. All good but..
global $wpdb, $current_site;
if ($current_site->blog_id == $wpdb->blogid)
The kicker is if I happen to post in the main blog post-indexer understandably ignores that post but that leaves Global-Search ignoring it also which is a problem.
I suppose I can create another blog for any "main blog" type posts but I wanted to check if there was a way around it. Unlikely but I thought I'd ask first.