Hey. You need to be able to load a custom theme. If you can’t do that (because you’re in a starter plan), then there’s not an easy fix.
If you can upload a custom theme, then you need to download the theme, find where it is making the #get request responsible for those posts, and add a filter parameter. Then zip and upload. It’s a small enough change that you don’t need a whole dev environment. Just unzip, notepad edit, and recipe. (I like 7-zip but anything you have that will unzip and rezip will work.)
If your theme has a home.hbs, start there. If not, start with index.hbs. Then look in the partials folder for the partials it is including. Not at my desk this morning, so you’ll have to do a little detective work!