I know you have been updated by our developers on this, but I just wanted to update the forum topic for anyone who is following it.
This feature is now available in the Google Calendar connector. Just click "Add optional fields" in the Create event action, and select the "Guests can modify" field and set it to "Yes". Let us know if you are facing any issues in this!
Send us a ticket, we will try our best to assist you with your problem