Using socket.io from a module

My sio = require('socket.io').listen(app) is in my server.js file, but I'm calling a method in a library that would like to push a message to the client... say api.user.pushToClient()

How am I able to access sio.sockets from there? Perhaps my structure is incorrect?

Folder structure:

server.js

api

|--user.js

|--another.js

in server.js append this line

module.exports.sio = sio; 

in api/user.js

sio = require('../server').sio;
sio.sockets.on ...

Or did I misunderstand the question?