Stream Non-Entry Files

I'm trying to also stream files that the entry file requires is this possible?
I have been looking for a while and haven't found innate to browserify or a plugin.

Simplified Example:
```javascript
const str = require('string-to-stream');
const browserify = require('browserify');

const entry = "const func = require('./func.js')";
const func = "module.exports = function() {return 'func'}";

browserify(str(entry), {basedir: __dirname})
// somehow map './func.js' to func string
```