Surya,
There are two solutions.
1. On the report of Users to be Notified, make a formula URL button to update a a date/time field to now() and then set an email Notification to fire when that date changes. You would filer the report so that it would not include records which have had that date updated today. The UIRL button would also refresh the report, so basically, you would click each record to trigger the notifications and just keep mindlessly clicking until all the record where gone.
Once that is working, you can then make an Automation to do the same thing - update all those records. In my testing, the Automations run slow enough that they are all considered to be separate updates by Quick Base (and not a mass update) and the individual Notifications will fire. So you could trigger the Notifications by clicking on just one record to fire them all (ie by starting the Automation).
