What is the default methodology used to limit the number of Customers selected for Dunning

We are working on (re)implementing the Dunning Functionality for PeopleSoft Receivables and possibly look at Customer Statements. Our user base is wondering what the preferred method would be to limit the nbr of Customers for which they want to activate Dunning/Statements. They simply do not want to do this for all Customers.

It looks like there's several ways to do this:

• Set the Dunning ID at the BU options level will apply dunning for the entire BU and all Customers will be included in the dunning process
• Set the Dunning ID at the BU options level and assign all Customers to different groups and you run the process only for a specific group which we want to use for Dunning on the correspondence options. If using groups, how do you classify these groups?