If an event syncs to a third-party calendar such as Google Calendar, then that means that it is a calendar that you are subscribed to. The sync process includes exactly the list of your subscribed calendars, no more, no less. So the only way to cause an event not to appear on a synced calendar is to unsubscribe from that calendar (which is probably not what you want to do).
If the events on a subscribed calendar do not appear on the main calendar display, then that is an indication that you have not checked the box by that calendar name requesting that those events be displayed. Checking that box will cause those events to display.
Questions that can benefit the larger community should be asked in a public forum, not a private message.