I try to build a multisite structure which is configured as a single site.
All categories, tags and posts need to be indexed: if we click on a category, all posts of all sites need to be shown. The same with the tags. And all posts need to be shown in the home page of the main site.
I know, you have post indexer plugin, which works with few other plugins. But If you have any advice to build this structure correctly, it is welcome.