Authenticate unique streams keys for restreaming

[StellarFr0st]

So I want to restream to multiple different providers (kick, twitch and youtube) however. I can only supply 1 stream key, so how can i do conditional statements or something that says, if the stream key (name on the admin dash) is this, then stream to these rtmp urls, however if it is that stream key, then stream to those rtmp urls?