Platform overrides

We have a game with iOS, GooglePlay, Amazon, Facebook Gameroom, Steam and Discord versions.
At the moment moving between things like Amazon->GooglePlay and Steam->Discord->Gameroom are a huge pain and requires changing settings on plugins so they are included/excluded for the right build as well as adding/removing custom defines.

It would be a HUGE help if we could just extend one of the platforms and create a new one.
For example create a Discord platform extending from Standalone, or a Amazon platform extending from Android. This way import settings would not need to be changed every time.