How to make vanish players visible to other vanish players?


For eample we have a server. And we have two types of users - players and spectators.
How can i make spectators invisible for players and for other spectators - semitransparent?


Sadly this capability is not available to developers yet so we can not create a plugin. We can make the player vanish completely but not to some.

We need this added into Sponge for us to develop plugins to do that.