code: public String getGroupName() {
  		if (TabSetType.ACCORDION.equals(getType())) {
  			CollapsibleGroup group = getComponentModel().group;
  			return (group == null ? null : group.getGroupName());
  		}
  		return null;
  	}
docs: The "collapsible" group name that this tabset belongs to.
  
  @return the collapsible group name