Keeping track of which boundaries went into which boundary groups and which DPs went into each boundary group can be tedious! In a fluctuating network environment, it can be flat-out daunting. This SCCM SSRS report allows you to see the Boundary Group to Boundaries relationship. It also reflects the Boundary group to Site Server relationship. I have included a couple of fields to permit auditing by modified on date and modified by fields. All you need to do is update the Data Source to your own instance.
More details can be found here.