How to define delivery hours in automessage

Hi,

I've found several threads on the autosend days in automessage.

This is the code I've found:
define('AUTOMESSAGE_POLL_MAX_DELAY', '31')

My site needs to send automessage every 3 hours, that means 8 messages per day to my team members.

How can I define the hours in the code?

Best regards,

Vi