[Plugin: Random / Rotating Ads V2] Can template code be used via functions.php?

I’m an trying to determine if I can use the template codes for various ad groups in my functions.php file and add them to an action hook rather than in a template. I’d like to deliver the ad groups via a conditional if(is_page(‘pagename’)) $ads=’template code’; sort scenario.

Is this possible? I can use the following function to deliver static images to these pages. Is there a way to user the template code in place of the image names?

function aside_ads(){?>
<div id="asideads">
     <?php
        if (is_page('about'))
         $banners='banner_abt.jpg';
			}
			elseif ( is_page('it-managed-services') ) {
			$banners = 'banner_man.jpg';
			}
		?>
     <img src="<?php echo bloginfo('wpurl') . '/wp-content/themes/uploads/' . $banners; ?>" /> </div>
<?php }
add_action('thematic_abovemainasides','aside_ads');