Sort Records Within Data/Range Blocks

I have around 50,000 records in a data file within which groups of records are contained in blocks delineated by date/time. e.g.;

A B C D E

10/03/2008 13:15 a 100.0
10/03/2008 13:15 b 2.8
10/03/2008 13:15 c 50.5
10/03/2008 13:15 d 8.6
10/03/2008 13:15 e 32.5
10/03/2008 13:25 75.2 <-----Time change
10/03/2008 13:25 5.5
10/03/2008 13:25 16.5
10/03/2008 13:25 3.5

etc

As you can see, while the file is ordered by date/time in Column A, the values in column E are randomly ordered.

My objective is to maintain date time order but sort the values in Column E into an ascending order within each block. So, for example, using the details above I would want it to look like;

A B C D E

10/03/2008 13:15 b 2.8
10/03/2008 13:15 d 8.6
10/03/2008 13:15 e 32.5
10/03/2008 13:15 c 50.5
10/03/2008 13:15 a 100.0
10/03/2008 13:25 3.5 <-----Time change
10/03/2008 13:25 5.5
10/03/2008 13:25 16.5
10/03/2008 13:25 75.2

Note that there is data in columns B to D which would need to be sorted in line with Column E. So, all records in the block, cols A to E are sorted to give the above order for each time block.

My problem is that I'm not sure whether a basic sort can do the job or whether a macro is needed. I'm using Excel 2003.