Google Calendar API (V3) send more invitation

Google Calendar API (V3) send more invitation

I'm using Google Calendar API V3 (php version) to create and update
events. I can send invitation while creating the event but I want to send
more invitation (add more attendees) while updating the event. But using
following call I have to create the whole attendee list again and
invitation emails are also not sending.
https://developers.google.com/google-apps/calendar/v3/reference/events/update
What I want to do is add more attendee using the API and send invitation
email to new attendee only without affecting the previous attendees. Is it
possible to do it using this API. Please help me!