Spam filtering based on topic/subject line

I'm using Thunderbird email client with Norton 360.

Lately I've been getting up to 5 emails a day selling Viagra and cialis, with a link which may be genuine or just phishing. Each one is copied to several addresses at my ISP, so probably they come from a compromised address book.

At the moment these emails are not being flagged as suspicious or junk by Norton. Each one is marked as coming from a different email address, so I can't block on that.

Surely there's a way of getting Norton 360 to tip these emails into the Spam folder. Another computer using Bullguard is able to place them in a 'deleted' folder. Why can't Norton do this?