Is there a way to hide some events from an Outlook calendar?
You can move those items you don't want to view in your phone into a new 'reminders' calendar, then disable that in your phone, however this has the shortcoming that other staff in our org do not see the free/busy information of that 'reminders' calendar. If I could fix that problem this would work for me.

related question: https://superuser.com/questions/636605/how-do-i-share-free-busy-info-from-an-outlook-subcalendar