Zip file contains UNDPs for MS DHCP Scopes, a sample alert and a sample report.
The alert contains some custom properties in the email message that you will want to delete.
Caveat: Since the UNDP is table based, the alert stops at the first matching scope that exceeds the trigger. You'll want to check the report to see if more than 1 scope has exceeded the trigger threshold.
The report is very basic, but it does show information that is useful for monitoring split-scopes.
Hopefully, somebody smarter than me can take this to the next level... (e.g. / incorporate split-scope awareness in the alert...)