Other people items shown in calendar view

I have a calendar where I show all my subitems per day (all my tasks are in the subitem level and in the item level I have a process or a project). From this calendar view I plan may week and I use it to check the activities due for the day. I´ve been facing one obstacle though. When a item is assigned to one person and a subitem of this item is assigned to another person, both see the subitem in their calendar view. I wish only the person with the subitem assigned would see it.