Hi I'm having a problem again with my project, I can't seem to get it going again.

Here is my table with 3 column,
I need a formula that will check the Column B and also the range inside the cell, and if it has a duplicate I want to show in the Column C he message "Duplicate Range" else "Valid". As we can see in the sample there are two row in col B that has duplicate, 200008-200020 and 200019-200030

the duplicate in both cell will be
200016
200017
200018
200019
20002

------A------------------------------B----------------------------------C
Column Name------+-------Column Range---------+---------Column Availability
Jason -------+------- 2001-2004------------+---------Valid
Richard -------+------- 20015-20017------------+----------Valid
Derrick --------+-------200008-200020-------+----------Duplicate Range
Matt --------+-------200016-200030--------+---------Duplicate Range