Call method a JS file that includes my file

Parent file : Parent.js

exports.execute = function execute(request) {
    var result = executeChild(request);  // Will not work as the executeChild function is not in this file.
    return "Hi!";
}

Child file : Child1.js

common = require('common');
execute = common.execute;
function executeChild(request) {
    return "Hello1";
}

Child file : Child2.js

common = require('common');
execute = common.execute;
function executeChild(request) {
    return "Hello2";
}

All the users of API call the execute method and they have no idea about the Parent child (OK may be its not a real Parent child relationship) relationship. How to make this function call (execute child) work.

NodeJs is used to execute this.

I would try to update the functions in the child files as a last resort and not before.