Only allow specific selection in datepicker

Only allow specific selection in datepicker

I'm very new to jQuery and I'd like some help with the date picker. I'd like to use the "multiple months" demo with a slight twist. I'm creating some time reporting software and each pay period is 2 weeks long. So if an H. R. rep would like to see hours for a specific pay period I'd like them to use the date picker. Now I want the picker to only allow selections of 2 week intervals (but it can't be a simple select 2 weeks from the current date). For example our first pay period this year was from 1/3/2015 to 1/16/2015 so if they tried to pick any dates within that range it'd select the entire date range of the pay period.

Each pay period always starts on a saturday and ends on a Friday 2 weeks later. My H.R. person wants an easy way to say "I want to see all the time from pay period 1 - pay period 6" and have it build a report off of that date range.

Any help would be greatly appreciated.