Need to select record from the group of records

Hi

I have this statement

SELECT * FROM ENT6418 WHERE VBELN >= '0090000000'.

             MOVE: ENT6418-PERNR TO REC-VRTNR.
             PERFORM GET_INVOICE_NUMBER.
             CLEAR: REC, TEMP.
ENDSELECT.

It works fine but the problem is ENT6418 has multiple records for the same VBELN

Is there any statement that I can use so that it selects only one from the multiple records

This is what I want

0090000001--|

0090000001 | select one of these

0090000001--|

0090000002<-- select this one

0090000003<-- select this one

0090000004--|

0090000004--| Select One of these

0090000005<-- Select this one

Please Help