Is it possible to filter messages in Gmail based on the URL of a link in the message?
For example, if the email includes text similar to the following:
For more information, use your local search engine.
I'd like to filter based on "http://google.com".
For background: I've been receiving emails from various political campaigns, and while they have different senders and mostly different text, the host in their unsubscribe link is the same - I'd like to bin them on that basis.