Name Space for PubSub

I'm using Django, Redis, nodejs and socket.io and having troubles solving a certain problem.

Suppose we have a chatroom with redis I and the pubsub pattern. On the nodejs server I listen for a Redis publish and emit the message to all the listening sockets. This is straight forward since on the nodejs side I have

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var redis = require('redis');

io.on('connection', function(socket){

    var pub = redis.createClient(), sub = rediscreateClient();
    // we have multiple chat rooms, suppose variable chatroom is passed from the
    // server when the page is rendered
    sub.subscribe(chatroom);
    ...
    sub.on("message", function(channel, message){
        socket.emit(chatroom, message);
    });
});

now suppose I want to extend this so that there's a 'like' button for each message. How do differentiate between someone sending a message or someone liking a comment, some sort of namespacing would be helpful, if I could do something along the lines of:

io.on('connection', function(socket){

    var pub = redis.createClient(), sub = rediscreateClient();
    // we have multiple chat rooms, suppose variable chatroom is passed from the
    // server when the page is rendered
    sub.subscribe(chatroom);
    ...
    sub.on("message", "message-sent-namespace",function(channel, message){
        socket.emit("message", message);
    });

    sub.on("message", "message-liked-namespace",function(channel, message){
        socket.emit("like", message);
    });
});

any suggestions? the publishing is done on the Django side.