how to select certain xml group based on attribute id and return as xmltype

[chanveil]

hi,i have an xmltype column name "NM" in table "XMLTEST", the content of the xml in NM is<ct><sp id="ALEX"><sp id="JOHN"><sp id="MIKE"><sp id="CALEB"/><sp id="PAUL"/></sp></sp><sp id="MAX"><sp id="WAYNE"/></sp><sp id="MAX"/></sp></ct>The group i want to select is ALEX except group "MIKE" and "MAX", which return<ct><sp id="ALEX"><sp id="JOHN"/><sp id="SEAN"/></sp></ct>Is it possible? i'm processing this using stored procedure PL/SQL, my environment is 11g R2 Win 32bit.please advice