Is it possible to "alert" based on a cron-style string?

[Marcus Mülbüsch]

Hello list,

   I have checks that I don't want go get an alert mail if it triggers 
and thus fill my mailbox. Setting "noalert address@hidden" works.

   However, at night and at weekends I'd like to get an alert mail. 
Right now I can only think of setting up to checks, one with "EVERY 
[cron]" and sending mail and the other with "NOT EVERY [cron]" and not 
sending mail.

   It is possible that way, but doubles the number of entries and thus 
is hard to maintain. Is it possible to apply a cron-style setting to 
just the alert statement, either globally or per check?

   Thank you,

Marcus