Multiple Blog installations – All posts on one page and seperate blogs

Might want to use Feeds for that or even just an RSS widget if you want to show the posts in a sidebar on those other blogs.

I have found my solution. I downloaded this plugin that allows each category to have a different theme.
https://download.mikelopez.info/2006/10/17/wordpress-themed-categories-plugin/#comment-113332
Then on the templates on the sub blogs, change the category code to this

<ul>
<?php wp_list_categories('orderby=id&show_count=1
&use_desc_for_title=0&child_of=8'); ?>
</ul>

Have the sub blogs in categories and it appears that the blogs a separate. Then use permlinks for the categories so your URL looks like https://www.mainblog.com/blog1 https://www.mainblog/blog2 etc, then have the subdomains point to those locations.

Theres probably a better way, but this way works.

The only thing is that I yet do not know how to remove the category work when I change the template to that code above.