Exim System Filter to Block Forwarded E-Mails to Specific Destinations

I would like to create a custom Exim system filter that can prevent e-mails from being forwarded to certain domains, such as Gmail.com, Hotmail.com etc. Is this possible? I've looked through the Exim documentation and there's nothing listed about SRS variables, and I can't seem to determine how Exim would realise an e-mail is being forwarded. If it's helpful, I have SRS enabled within WHM. Thank you for any assistance.