swap panels from child element

[Chris]

Hi,

I would like to swap panels B and C when the user clicks on a certain div 
element in Subpanel Aa

The Page consists of following panels:
- Panel A > Subpanel Aa
- Panel B
- Panel C

How can I access the panels B and C and replace them or change their visibility 
from the WebMarkupContainer onEvent(AjaxRequestTarget target) method?
Is it better to replace them or change their visibility?

Subpanel Aa:
…
WebMarkupContainer div=new WebMarkupContainer(„item");
div.setOutputMarkupId(true);
div.add(new AjaxEventBehavior("onclick") {
    protected void onEvent(AjaxRequestTarget target) {


    }
});
...

Thanks,
Chris