That's an interesting idea. It might be the simplest way to automate space platform requests.
Unfortunately, Logistic Group Combinator updates every tick (because there seems to be no other way to read circuit network in Factorio) and resets request filters on every tick. So there's practically nothing another mod can do to fix that.
It's still doable, but Logistic Group Combinator needs to be updated to raise an event whenever it changes the Logistic Section. It also needs to respect already set planet filters when updating.
I might take a deeper look at the Logistic Group Combinator and make a PR, but probably not any time this month.
There's also hope that version 2.1 might bring better space platform request management, so perhaps there's no reason to rush this.