Here's how I ended up solving this.
In the defaultdate setting for my enddate datepicker, I put the following formula If(dtStart.SelectedDate<Date(Year(Now()),7,1),Date(Year(Now()),7,1),If(Year(dtStart.SelectedDate)>Year(Today()),Date(Year(dtStart.SelectedDate),7,1),Date(Year(Now()),12,31)))
By doing this, I was also able to address the issue if someone selected a start date for the next calendar year