Você poderia fazer algo assim:
SQL> SELECT *
2 FROM (SELECT empl_id, ename, report_to,
3 member_id, board_position,
4 MAX(lvl) over(PARTITION BY empl_id) maxlvl, lvl
5 FROM (SELECT connect_by_root(e.empl_id) empl_id,
6 connect_by_root(e.ename) ename,
7 bm.empl_id report_to,
8 LEVEL lvl, bp.*
9 FROM emp e
10 LEFT JOIN board_members bm
11 ON e.empl_id = bm.empl_id
12 LEFT JOIN board_positions bp
13 ON bm.member_id = bp.member_id
14 CONNECT BY NOCYCLE e.empl_id = PRIOR e.report_to
15 AND (PRIOR bp.board_position IS NULL
16 OR PRIOR bp.board_position != 'LDRSHPCOMM')))
17 WHERE lvl = maxlvl;
EMPL_ID ENAME REPORT_TO MEMBER_ID BOARD_POSITION
------- -------------------------------- --------- --------- ------------------
FLUNKY Ida Dunnit INFGUY CIO LDRSHPCOMM
HITECH Number 2 INFGUY CIO LDRSHPCOMM
INFGUY Comp U Turk INFGUY CIO LDRSHPCOMM
LOTECH Number 3 INFGUY CIO LDRSHPCOMM
OPSGUY Meikut Work OPSGUY COO LDRSHPCOMM
PROGMR Nameless Blameless INFGUY CIO LDRSHPCOMM
TOPDOG Big Guy TOPDOG CEO LDRSHPCOMM
WALLET Money Bags WALLET CFO LDRSHPCOMM
Não tenho cláusula START WITH porque quero iniciar a consulta hierárquica para todos os funcionários. Para cada funcionário, percorro os dados hierárquicos até encontrar um gerente que seja membro do conselho no comitê de liderança (cláusula CONNECT BY).
As consultas externas filtram as linhas relevantes.
