Sorry if this is in the wrong place. Feel free to move it but since this seems to typically involve JavaScript I thought it matched...

I have a 1,080px by 270px area at the top of our site/blog/forum that i use to randomly display images linked to our blog posts. Not for actual 3rd party ads or anything.

CURRENTLY I have it divided into 4 equal square divs 270px each. Then each one has a different ad zone assigned. I have purchased an expensive ad server subscription to push the ads randomly to each of the squares each time a page is loaded. I have it setup to never display the same ad at the same time obviously. BUT, the biggest reason I paid an adserver was because every 10 page loads or so I like it to display one large/wide banner across then entire thing. I do this by slicing the one wide image up into 4 via photoshop and then assigning each square of the image into zone 1, zone 2, zone 3, zone 4 and then using a companion restriction so that if one of the images pop up it automatically loads the other 3 matching ones into their zones giving me one wide banner image.

I think this is really cool but it's very costly each month and a pain in the butt. Is there any easier way to get this same type functionality but without having to pay for an adserver since I'm not really serving 'ads'?

Thank you for any insight on this