Have you tried it yet:
SELECT tblParts.*
FROM tblParts
WHERE ID NOT IN (SELECT tblParts.ID
FROM tblParts WHERE
(DCOUNT("1","TBLPARTS","ID=" & [ID] & " AND ISNULL(IDSUPERIOR)=TRUE")>0 AND
DCOUNT("1","TBLPARTS","ID=" & [ID] & " AND ISNULL(IDSUPERIOR)=FALSE")>0));
result:
ID Name Level...