use exhost with page directive?

In my hobbit-alerts.cfg, I have a bunch of alert definitions that start

PAGE=Main/Subpage

MAIL emailaddress

SCRIPT /smsplus.sh

If I want to exclude a single host from alerting within the subpage, what's the best way to do this?

I tried PAGE=Main/Subpage EXHOST=testhost, but I'm still getting alerts on it...

Are the page and exhost directives not compatible?