If not running them at the same time is a requirement, you need to implement some additional logic. Perhaps wrap each of the scripts inside a wrapper which decides whether to run or not, based on your criteria, or based on the existence of a lock file (but then you still need to figure out how to make the correct one run and create the lock file in the first place).

Actually maybe it's easier to have a single cron job which runs a script which decides whether it should run the monthly, weekly etc job.

@incredible: what does redirection have with this to do?