Disable Alert for Specific Server at Specific Time

This is what you would use the Unmanage Scheduling Utility for. Simply create a scheduled recurring unmanage window for the node. During this time when the node is unmanaged any alerts configured should be suppressed. The server being "down" while unmanaged will also not count against the server's availability statistic since this is considered to be a planned outage.

Thank you for your prompt response.  Hopefully this will take care of one annoying daily email and I learned something new in the process.