Nginx rtmp how to only accept 1 streams key.

Hi, i am trying to create a plataform to stream rtmp.
so i need create a custom streams keys for users and not allow all stream keys.
Example: in nginx you can stream with anyone key like this: rtmp://server/live/anyonekey.
I need to trasmit to only one key and block other keys.
Like this

rtmp://server/live/server1 Accept
rtmp://server/live/server2 Deny
rtmp://server/live/server3 Deny
.............