I took what Sean put together and added a little more sample data (a second order number) and changed it up a little. If I am correct you need the difference between the PUP and DRP that relate to each order number. Let us know if this does is what you need.

if OBJECT_ID('tempdb..#Something') is not null

drop table #Something

create table #Something

(

OrderNum int,

Location varchar(10),

PUPDRP char(3),

SomeValueOfSomething int,

StopTime datetime,

col tinyint

)

insert #Something

select 1303927, 'Whouse1', 'PUP', 4394903, '2013-08-11 07:26:33.000', 1 union all

select 1303927, 'Store1', 'DRP', 4394904, '2013-08-11 08:31:46.000', 2 union all

select 1303927, 'Store2', 'DRP', 4394907, '2013-08-11 09:28:57.000', 2 union all

select 1303927, 'Store3', 'DRP', 4395040, '2013-08-11 10:38:53.000', 2 union all

select 1303928, 'Whouse1', 'PUP', 4394903, '2013-08-12 07:26:33.000', 1 union all

select 1303928, 'Store1', 'DRP', 4394904, '2013-08-12 09:31:46.000', 2 union all

select 1303928, 'Store2', 'DRP', 4394907, '2013-08-12 11:28:57.000', 2 union all

select 1303928, 'Store3', 'DRP', 4395040, '2013-08-12 12:38:53.000', 2

select d1.*, DATEDIFF(HOUR,d2.StopTime,d1.StopTime) AS TimeBetween

from #Something d1

JOIN (SELECT OrderNum, StopTime FROM #Something WHERE col=1) d2

ON d1.OrderNum=d2.OrderNum