How to limit guests to Quick Search only?

As the title says, how i can prevent guests switching to simple or advanced search after they did a quick search on the homepage.

Does this need to be changed in the base code? i cannot find it in the page builder on how to do this.

Hope somebody can help :)
Thanks in advance

Solved by myself.... just added an if-statement

if ((int)$_COOKIE['memberID'])
{ ... } else { ... }

around the $sLinks = BxDolPageView::getBlockCaptionMenu(mktime(), array( ..... ) code-block in /search.php