Can I merge calendar on my mac with a calendar on iCloud?

Hi

I have a claendar that shows on the dropdown list as the default calendar ON MY MAC. It syncs with my microsoft outlook calendar at work so I can see all my work calendar items on my home mac.

The drop down list also shows iCloud as having a separate calendar. When I untick the ON MY MAC calendar all my appointments disappear. I'd like to merge these calendars together so that I can also see the work appointments etc on my iPhone. Does anyone know if this is possible, and if so how I can do it?

Thanks very much

Andy