Manage calendar invitation with Gmail Apple ID

Ciao all!

as Apple ID I use a Gmail account and when I receive an appointment it is associated to the G Calendar, without any chance to select the iCloud calendar (where I set all my calendar).

On the reverse, when adding a new appointment I can choose to which calendars it belongs to and the receiver see the invitation sent by my Gmail account.

How can I select the proper calendar when accepting incoming invitations? Is it a limitation due to the Apple ID and Gmail or it exist a setting to manage this?

As i can see, this problem is shared between any product I currently have (all updated to the latest version) Ipad mini, Iphone and Macbook Air, but mainly i would like to solve this issue on the Iphone!

Thanks for any help

Ciao

Filippo