SEO question

I have in my layout:

echo $this->Html->meta('keywords', $keywords);

echo $this->Html->meta('description',$description);

 

Where $keywords and $description get pulled from my settings table so admin can edit those as they wish.

 

Now I have content pages which allow admin to add keywords / description specific to that page and need a way to override the original set values for each / if not fall back to original values from SiteSettings and cannot seem to figure out the best way to go about this.

 

Ideas? Suggestion?

 

Thanks,

Dave