When other users have shared their calendars with you, there are two options for the manner in which their schedule data is presented to you:
1) All calendars which have been shared with you will be listed in the Calendars Shared Tab of your Calendar view. Simply click on the users name within the Shared tab in order to view only that individual’s calendar.
2) To view your own calendar overlaid with the calendars of one or more other colleagues, check the boxes of the users whose schedules you wish to see overlaid on your own. This feature can greatly simplify the scheduling of meetings.