Problem: Can't see posts from all my ActivityPub instances all at once

[ghost]

Pitch

Wouldn't it be cool to have a timeline that is somewhere between the local and the federated timeline? It shows the local posts and posts from a selected set of other instances.

Motivation

I have the Ecko instance social.wien.rocks, a Pixelfed instance pix.wien.rocks, a Peertube instance tube.wien.rocks, a WriteFreely instance write.wien.rocks a Funkwhale instance funk.wien.rocks and as soon as I get it to install a Mobilizon instance mobi.wien.rocks. They all belong together and I'd love for Ecko's "local" instance to display posts from all of them.