I created a server task that runs a query every hour. The query is based on the Inactive machines query, though I changed the criteria to look for machines in my sync point folder that have checked in to ePO and become "Managed" within the last 2 hours. The machines enumerated by this query get their sorting status changed to enabled. Then it performs a wakeup call to get sorted appropriately either by tag or IP address.
Hope this helps.
Thanks Mark, good idea - that sounds like the best bet ...