Rick,
To the best of my knowledge, there is no information on how to consolidate two OpsMgr instances into a single. They each maintain their own unique DFM database and there is no documented process for merging them.
If you just need a single pane of glass for reporting, you can look into OnCommand Insight Reporter (OCIR). It is designed to collect information from multiple OpsMgr servers and provide a consolidated view of your data. However, its just for reporting, not monitoring or alerting.