Calendar events relating to trial

I would like to be able to enter the date of the trial and be able to enter all events leading up to the trail. Such as Trial Date is 01-01-2050 and 20 days before trial witness are due and 40 days before trial experts are due, etc. I want the dates to be calculated and and events placed on my calendar. I would like to be able to change the date of the trial and all event dates be changed and updated on my calendar.