How to create Email Digest from Portal UWL entries

Can we create a portal background task.. which will fetch all new UWL entries (for today's date) and combine and send as email digest to User's Outlook Inbox? I think using UWL API we can extract the individual workitems in worklist.. however is there any configuration which I can disable systems email service from sending all portal workitems to outlook inbox... but at the same time allow this background task to send email digest at the end of the day?

Thanks