RSVP’ing to Google Calendar Event via Simple Calendar

I currently manage a community of 100 people and provide them with access to a WordPress-based online portal where they can communicate with each other and view news updates from the community.

I also have a Google Group for this community, and I use that to send Google Calendar invites via email whenever I am hosting an event for the community (I send the calendar invite to the Group email address and everyone receives it).

I would like to continue sending Calendar invites via email but I also want to allow people to RSVP to the Google Calendar event in the portal if they prefer to respond on there. I have not found a solution that would enable this. I considered embedding the public Google Calendar where my events are all created as an iFrame in the portal. But that doesn’t seem to allow people to RSVP, they can only see the event. Please let me know if Simple Calendar would be an appropriate solution or if you know of any other solutions.

Thanks for the help.