Custom Data Validation for Dates

[karabiner8]

Hi,

Column B is a date column (Start Date) and I've used Data Validation to restrict the entries to dates after Jan 1, 2011. I've done the same in column D (End Date).

I'd like to restrict column D to be greater than or equal to column B. Is there a way to create a custom Data Validation that:
1) value must be a date
2) must be greater than or equal to Jan 1, 2011
3) must be greater than or equal to the corresponding date in column B.

If it is not possible I'd like to know too so that I don't waste anymore time on it.

Thanks

 

[karabiner8]

Got it.

Column B Data Validation
Allow: Date
Data: greather than or equal to
Start Date: 01/01/2011

Column D Data Validation
Allow: Date
Data: greather than or equal to
Start Date: B1 (or corresponding row in column B)