Table Query

Question

I need to query a table to return a unique set of "sets".  The table is structured as follows:
DetailID   HeaderID  SetID   ShiftID   Amount

DetailID is the primary key and HeaderID is a foreign key related to the Header Table.  The ShiftID is a foreign key to the Shift table.  The HeaderID will generally have multiple SetID's.  When the ShiftIDs and Amounts are the same with a different SetID I would like to return only one of the SetIDs and the related ShiftIDs and Amounts.  As an example:

Header	Set	Shift	Amount
973	1	171	10
973	1	138	2
973	1	157	19
973	1	123	13
973	1	172	5
973	1	153	2
973	1	163	5
973	2	171	9
973	2	138	13
973	2	166	6
973	2	157	12
973	2	143	12
973	2	123	2
973	2	153	1
973	2	168	1
973	3	171	9
973	3	138	13
973	3	166	6
973	3	157	12
973	3	143	12
973	3	123	2
973	3	153	1
973	3	168	1

Sets 2 and 3 are identical so I would like to only return sets 1 and 2 or sets 1 and 3 with the table headers showing.

Thank you