^That's not what the OP wanted exactly...
Anyway, you can't do what you're asking about until the following CSS4 feature is implemented: http://www.w3.org/TR/selectors4/#subject
Once it is, you can use something like example.com##$div>a[href*="adspam.com"]
where the $
indicates the element to actually apply the CSS to.
In the meantime, you can use mapx's rule along with the following: example.com##a[href*="adspam.com"]+p
This rule hides all p elements adjacent to a elements with href containing "adspam.com"; mapx's rule hides those a elements.
There's a buzzin' in my brain I really can't explain; I think about it before they make me go to bed.