cron: send email to different address in case of failure
Solution 1:
You'll have to do it in a wrapper script.
Solution 2:
No, cron send all output to the specified user.
Normally all cron jobs should have STDOUT redirected to /dev/null, because you don't want to spam the user with all cron jobs that run on the server.
If you would do this (the redirect), you will get the email only in case of failures.