Add event types to iCal but not new calendar

I'm moving over to iCal from Microsoft Outlook, using it for work. I like iCal because I can easily share my calendar with my coworkers, who are using Google Calendar. However on Outlook I was able to have different categories of types of events - such as one color for meetings at the office, another color for meetings offsite, another for phone calls, events, etc.

It seems like the only way to create "categories" of calendar events in iCal is to create a new calendar - but then it appears I have to share every single one separately with my coworkers. They don't need to see my categories; just that I have an event during that time. Is there any way to count this as just "My Calendar" that I share with my coworkers, and only internally have this different color/categories of events?