[jQuery] how can i find() including self?

[Mark Gibson]

With the follow style of markup:

<div id="my-combo" role="combobox" aria-owns="my-list another-thing">
</div>

<div id="my-list" role="list">
</div>

I need to find the first element of type [role=list], in either the
descendants
of #my-combo, or the elements (and descendants) identified in aria-
owns.

I was think of creating a plugin to make this easier:

$('#my-combo').owns('[role=list]:first');

$.fn.owns = function(selector) {
        // Gather all the id's from aria-owns attrs, appending '#' to each,
and separate with ','
        var include = $(this).filter('[aria-owns]').map(function() {
                return this.getAttribute('aria-owns').replace(/([^\s]+)/g, '#
$1').replace(/\s+/g,',');
        });

        if (include.length) {
                // Find all the referenced elements
                var owned = $(Array.prototype.join.call(include,','));

                // HELP NEEDED HERE!
                // Here I need to pretend that the 'owned' elements are also
children of 'this'
                // FakeElement(owned + this.children()).find(selector)
                // or
                // owned.add(this.children()).findIncSelf(selector)
        } else {
                return this.find(selector);
        }
};

I'm puzzled as to how to combine the owned elements and the
descendants of the
context elements, and find the using the requested selector.
Any ideas?

Cheers
-Mark