Object reference for an UI object from within another UI obj

How do you obtain the object reference for an UI object from within another UI object? Specifically I have a Tree object and a Grid object on the same display document, from the Tree I would like to get hold of the selected Row, so I can either grab values or change them. Is that possible?

In case other run into the same issue, here is what I did. I add a collection to the UI object that holds the Grid. everytime a tab is added or removed I update the collection, likewise for the Grid

var mcolTabProps;
var mcolGridProps;

this.TabProps = function() {
return mcolTabProps;
this.GridProps = function() {
return mcolGridProps;

this.Initialize = function(oUI, oMessageBox, oValidation, oXML, oError, oOrganization) {
mcolTabProps = new Collection();
mcolGridProps = new Collection();

        oTabProps                 = new Object();

//Populate with Tab attributes
mcolTabProps.add(oTabProps.ID, oTabProps);
var oGridProps = new Object();
//Populate with Grid attributes
mcolGridProps.add(oGridProps.ID, oGridProps);

In the Tree object I can then get hold of the Grid this way

    var sActiveTab = moUI.tabbarContent.getActiveTab();
    var oTabProps = moAlarmKB.TabProps().item(sActiveTab);
    var oGridProps = moAlarmKB.GridProps().item(oTabProps.GridID);