Dialog Load from External Source

Is it possible when executing the dialog.load command that it can link to and populate from an external file?

Here is a snippet of my code:

var myDialog =

{
initialize: function(dialog)
{
dialog.load({
"sub1":
{
"User1": -1,
"User2": -2,
}
});
}

I would like to have sub1 populate external file. Is this even possible.

Sarah