My understanding is that whenever someone you follow on mastodon makes a post, in kbin it shows up under Microblogs in the “random” magazine… I think… which is here:

https://kbin.social/m/random/microblog

but maybe you can narrow that down by using the “subscribed” filter? Maybe? (edit: yes, appears that’s how to do it, select the subscribed filter and then the microblogs tag for https://kbin.social/sub/microblog to see just who you’re following.)

I think things only show up in other magazine microblogs if someone on kbin specifically posts one to that magazine.

Still working things out myself. But it’s probably better to have a separate mastodon account and appropriate app to keep up with those posts and ignore the Microblogs tab because for some reason all comments are always expanded. Again, I think.

edit: correction already, it looks like everyone posting on Mastodon shows up in the random microblog, whether you follow them or not.