Accepting an invite in Outlook that you don't want to go into Orion's calendar

Note: Most firms are set to not sync appointments marked as private. If you have questions on that please contact Orion support. The below will only apply where we are not syncing private items. 

The first and best way is to have the sender mark the invite private when they are sending it. They can do this by clicking the lock icon so that it is highlighted before they send it.

The second and less reliable way is after accepting the invite to immediately go to the appointment in Orion and mark it as private. This is less reliable because appointments are set to sync every 3 minutes. The sync process goes through each User.  Using this way there is always going to be a possibility of it showing up in Orion if the user was not fast enough marking it private. I would recommend checking Orion's Calendar Manager to make sure it is not in there.