I have a model, with four date fields, example:

Initial Date Second Date Third Date Fourth Date

On the user entering a date on the "initial date" field, I want to trigger a calculation on the next three. Is this possible via the web interface in any way? I'd like to avoid creating a module, just purley for a simple list if possible. I was thinking perhaps there were triggers or on update or something that would allow me to do this? The calculation would be:

Initial Date 01/01/2013 Second Date as 18/01/2013 Third Date as 28/02/2013

Based on number of days from the initial date field.