Help: 3 column template with iframe possible?

Hello Everyone!

Here’s what I want to do:
Have a three column template on the main page where:
– 1st column is for all the posts
– 2nd column is the sidebar with widgets
– 3rd column is collapsible (with “hide/show”) and acts as an IFRAME to show links from the post. The links may be images, maps, or another site of mine. In the blog post there may be a link to a restaurant and clicking that link will act on the IFRAME 3rd column to display the page.

I hope that’s clear. If I cannot do “hide/show” can you recommend another solution (overlay like Lightbox but for links) where another browser window does not need to open?

Is that possible?

Thank you all in advance ??