We added Harmony integration in the latest beta. The current Activity synchronizes in both directions so that whether you start an activity from Roomie or Harmony, both will engage correctly. Keep your Activity names the same between the two. Just add your Harmony Hub via auto-discovery to the appropriate room in Roomie that corresponds to the room in which it is used and for which the Activities will match. From there, the synchronization is automatic.
There is also an .ACTIVITY START command to launch specific Harmony activities that you specify.
Beta is semi-public, but access requires contacting support if you have not previously been part of it.