CRON - more time-options available?

Hi there,

I just have installed e-Newsletter; actually the first newletter is being sent to app. 360 persons.

To prevent spam, my provider only accepts emails to max. 50 persons, followed by a break of minimum one minute.

The CRON-settings just allow weeks, days and hours, but not minutes. Is there a way to set it to minutes myself? I manage other newsletters with app. 2.000 addresses and don't want to wait 40 hours till the CRON-job is done...

thank you for any help,