Hi Rich
Sorry it’s taken me so long to get back to you. Your latest idea is great. It’s taken me a couple of days of troubleshooting to get the System started rule to work (grpList doesn’t have the members field so you need to call forEach on grpList itself) but now I’m able to retrieve a group by name 
I need to work on my VoiceCommand rule but once I’m happy with it I’ll post an update in my other thread https://community.openhab.org/t/voice-control-wit-ai-my-progress-setup-tips-advice-needed/2522