Some mail servers support what's called 'user+box' or 'plussed' addressing, where you can use an address of the form realname+magic. Email addressed to realname+magic@yourcompany.com will be delivered to the realname mailbox. It can then be filtered on for special processing, as the "+magic" part is preserved (think procmail http://wiki.apache.org/spamassassin/UsedViaProcmail ).
To find out if your mailserver supports this feature, simply test it out by sending email from somewhere else to "yourname+test@yourisp.com" and check if it arrives in the yourname mailbox.