Tag for generating posts from multisites?

Hi all. Here is my site I’m working with: https://www.mymythos.org/

As you can see there are some boxes on the front page which, when clicked, generate a page of posts in a nice layout.
Thing is I’m using multisite and need to be able to have member’s public posts generate in one of those boxes (Mythos Journals). However it doesn’t seem that there are any tags for Multisite which seems a bit odd. Am I missing something?

Just to rephrase: If you click the Mythos Journals box, I need it to display the latest public posts made by members who have created their own satellite blog using Multisite on MyMythos.org.

I think a tag for doing this would go a long way toward helping give Multisite a lot of community appeal.