Any advice and suggestion is appreciated.

I like to establish a group or public calender so that 8 people in my
department can manage resources better.  This public or central calender's
sole purpose is to keep track of each individual's sick, vacation, and time
off.

And within my own calender and all other members, I would like the option to
click on the "group calender" so that it'll display along my own calender.  
Also, each individual has the capability to add/delete his/her comment, but
not allow to update other's.

Thanks in advance.