How can I group two annotations with JavaScript?

Question

I create two annotations with JavaScript:
var annot1 = this.addAnnot({
                  page: 0,
                  type: "Square",
                  rect: [150, 150, 180, 180],
                  name: "OnMarketShare",
                  author: "A. C. Robat",
                  contents: "This section needs revision."});
var annot2 = this.addAnnot({
                  page: 0,
                  type: "Square",
                  rect: [200, 200, 300, 300],
                  name: "OnMarketShare",
                  author: "A. C. Robat",
                  contents: "This section needs revision."});
How can I group them with JavaScript?

Answer 1

Can I select them in JavaScript Code?
like:
annot1.selected = true;     //wrong JavaScript code.
annot2.selected = true;     //wrong JavaScript code.
annot3.selected = true;     //wrong JavaScript code.
annot4.selected = true;     //wrong JavaScript code.
If I can do these, I can group them easily : right-click them, and then, click "group" button.