how to could you please help us in group assignment of collectors for dunning

Summary:

hi
we understand as a part of configuration for dunning, we have to attach profile class (collector) to customer master and attach employee record to collector at the task: Manage collectors
Business required: Signpost has shared collector model where multiple uses take care of collection/ dunning process. their is no segregation of certain set of customer record being handled by a particular collector.

problem:
1. Having specific collector attached to customer master, ensure just that customer data being visible in the collection dashboard
2. having default collector attached to all customer master enabled only one employee record to be tagged in configuration and only one user can see the dunning dashboard.