How to reference parent modules in Node.js

I have a few files, requiring each other recursively.

routes.js requires api.js.

api.js requires upload.js, pixels.js, etc.

From upload.js or pixels.js I want to use fn's in api.js.

Currently I'm requring like so, but it doesn't work:

// routes.js
var api = require('./api');
api.upload.image(args); // a fn run from routes.js

.

// api.js
module.exports = {
    upload : require('./upload');
}

.

// pixels.js
module.exports = {
    get : function (args) {
          console.log(args);
    }
}

.

// upload.js
var api = module.parent.exports;   // <= tricky part
module.exports = {
    image : function (args) {
          api.pixels.get(args); // <= api is undefined
    }
}

The module.parent.exports are empty in the sub-modules, and I can't figure out how to require them properly.

How should I require to get this functionality?