How do I select and display multiple entries?

I am creating a worksheet using excel 2007. In one of the columns I need to select 1 or more options and then the same should be displayed in the data cell. Can I do it using data validation? Otherwise, which control can I use & how do I use it to select and display multiple items from a list of items in a single data cell?
Also, I would need to use it for further calculation/function. So please help me out with this.

I've attached the excel worksheet for reference. I need to implement this in Column F.