@ryunoki yes in general, imho just replicating data around is just not sufficient and becomes problematic when the network grows.
Okay, I’ll thinking about it. Maybe I come up with a clever (mathematical) solution 
I’ve written a proposition to reflect on how tha protocol can be updated to dd a bit of push mode in it. It participates to an effort to let features like post editing to be implemented in the federation.
This work can be seen on my github. This is still a draft. Please report any comments on how this proposition can be improved.
Please also note that I haven’t read that thread before writing this DEP.