Delay in email sending

My journal is hosted in a shared server where the number of emails is restricted to 60 emails per hour. If I send more than 60 emails in a single instance or more than 60 emails within an hour, all of my emails return-back to me. This always happens when I try to notify the users about the publication of a new issue.

Is there any way to create a delay between emails.

Similar kind of problem I have posted in old PKP forum website a few years back, but unfortunately, I am not able to find it.

With kind regards

Ganesh Sharma