Question about multiple AjaxSubmitLinks in one form

Suppose that I have one form which has two parts: each part has an AjaxSubmitLink and some other input components(such as TextField, CheckBox,...):
[code]
public class MyPage extends WebPage {
public MyPage()
{
        Form form = new Form(...);
        add(form);
       
        //Part1
        AjaxSubmitLink link1 = new AjaxSubmitLink(...)
        TextField comp11 = new TextField(...)
        CheckBox comp12 = new CheckBox(...)
        ListChoice comp1n = new ListChoice(...)
        form.add(link1);
        form.add(comp11);
        form.add(comp12);
        form.add(comp1n);
       
       
        //Part2
        AjaxSubmitLink link2 = new AjaxSubmitLink(...)
        TextField comp21 = new TextField(...)
        CheckBox comp22 = new CheckBox(...)
        ListChoice comp2n = new ListChoice(...)
        form.add(link2);
        form.add(comp21);
        form.add(comp22);
        form.add(comp2n);
}
}
[/code]

MyQuestion: when I click (AjaxSubmitLink link1) of Part1, I want to prevent Part2 to submit their data( and their backend Model object). What can I do ?