Password vor sysadm_r

Hi there.

Ist there any chance to set a different password for the sysadm_r role 
than the root password?
Excuse me if my questions seem dumb, but im doing my first steps in SELinux.

Lets describe my goal:
I want to let cron do its job as its supposed to do.
But : I want manipulation of the scripts getting lauched by cron only to 
be possible in sysadm_r.
And i want the command "crontab -e" only to be available in sysadm_r.

Thanks and I hope nobody will lose patience 

Many kind regards,
Markus