Block any user at an IP range for a SINGLE user?

We get some spam and some legit mail from hotmail servers.  I have one user 
that wants me to block it all.

Normally, I would run

xlist.pl black ip hotmail.ips.go.here

to block all mail from that IP or range of IPs.

It is possible to make a non-expiring entry in the database that has the IP 
and a single rcpt_to address (e.g. [email protected]) and have the script know 
to block that mail - but do the normal greylist for that same IP if the 
rcpt_to is anyone else at the domain?

If I can't do it by IP, can I add a triplet that has IP a mail_from of 
"@hotmail.com" and the [email protected] as the rcpt_to?  In other words, from 
this IP block any mail from any hotmail users to this local user?

Thanks,
Dennis