I know I am able to set permissions for users/groups to make certain areas of my site or "blocks" visible to registered users but not to guests. However, when I hide these blocks, the pages are not visually appealing. The blocks drop out of the page layout and leave gaping holes.

Here's the question: Is there a way to set up the permissions on a given block so that the block is visible to everyone, but when a non-registered user selects that block they are presented with the login/register screen?

Thanks in advance to all who respond.