Multisite - Images to display only on specific sites.

Hi,

Currently I have a carousel setup that displays 5 images. I also have the drupal site serving 21 domains (multisite).

I'm looking to change the carousel to display the 5 images above and extra images depending on the site.

I tried creating a new field and then filtering the field using the site:url so that only certain images display for particular images.

I run into the problem above where I cant target the specific site for certain images.

The view filter is like so :
 

Content: Url (contains [site:url]) 

In the content field I tried adding int the url field the url test.com so that an image only displays on that domain.

Is there anyway to do this? Can you use the [site:url] token in a content field? or is there a more elegant solution to this problem?

Thanks,
Ian