How to send unique orders by email in a custom schedule?

Does anyone know if we can schedule emailing of results of a SO saved search every 2 or 4 hrs somehow? I am also trying to send unique orders in every email - so for instance the orders that show up in the first email will not show up in subsequent emails - not sure if both of this can be done somehow with workflows or will scripting be involved in achieving these?
I have checked with support on custom scheduling of emails (like every 2 hrs or every 4 hrs) for saved searches and it seems it is an enhancement!
I also have an idea for the unique orders being sent in every email - maybe have a custom checkbox field checked for orders that were sent in each email and in the saved search have a condition to display orders with that checkbox unchecked. Maybe this approach can backfire somehow but I wanted to check if this makes sense or someone have a better idea?