Hide (or disable) an entry field in CP depending on user group permission?

Question

So I am trying to hide (or disable) a field in the "Edit Entry" view in the CP.

I know how to test a user group :
{% if currentUser.isInGroup('groupHandle') %}

But I cannot find a hook in Craft Doc to change the rendering of my field ? Perhaps with getInputHtml()? But I dont understand exactly how...

Answer 1

OK so here is my solution :
1/ define a custom permission for user groups

public function registerUserPermissions()
{
    return array(
        'updateTopNews' => array('label' => Craft::t('Update Top News')),
    );
}

2/ simply add css to hide the field when user has not the permission in my plugin init function

 public function init () {
    parent::init();

    $user = craft()->userSession->getUser();
    if ( craft()->request->isCpRequest() && $user ) {

        if ( !$user->can('updateTopNews') ) {
            craft()->templates->includeCss('#fields-topNews-field { display: none; }');
        }
    }