Sending an automated alert 1 hour before the Sending Time of a sub item.

Hi Team,

We are looking to send an automated alert 1 hour before the Sending Time of a sub item to subitem assignee person for one of our boards. As I currently checked with the support team, the feature doesn't seem to be available as only the reminder can be sent on a specific time of the same day of the event or days before or after.
However, we are looking for the feature as we frequently use it on daily basis and need to add as a reminder to already occupied customer support team.