Expand / Collapse particular category in a view in XPages

In XPages, you can expand all / collapse all categories in a view either using the expandLevel property of view control or using view control API. The API technique can further be extended to expand / collapse a particular category in a view. So to expand the code goes like this:

var viewPanel = getComponent(compositeData.viewPanelName);
var model:com.ibm.xsp.model.domino.DominoViewDataModel = viewPanel.getDataModel();
var container:com.ibm.xsp.model.domino.DominoViewDataContainer = model.getDominoViewDataContainer();
container.expand("1");

This would expand the first category. To expand sub categories you would pass the argument 1.1, 1.2,... to the expand method. Unfortunately this method only works by indicating position of categories rather than value.

For collapsing the code goes like this:

var viewPanel = getComponent(compositeData.viewPanelName);
var model:com.ibm.xsp.model.domino.DominoViewDataModel = viewPanel.getDataModel();
var container:com.ibm.xsp.model.domino.DominoViewDataContainer = model.getDominoViewDataContainer();
container.collapse("1");