OAF fields tracking in supplier page

Hi,

The following is a requirement:

To track a few listed fields in supplier setup OAF page; when any of these fields are updated(committed to database), an email must be triggered to a group.

Two things came to mind:

1) Search for Business events that would be triggered when supplier details are updated, and check if event parameters that are passed include these fields in the requirement.

If they are included, I'm not sure how tracking could be done using this as there would have to be a mechanism to store old values for these fields, and since there are thousands of suppliers and sites, this seems inefficient.