Oracle Group by a String column by string concatenation of its values

CREATE OR REPLACE VIEW SOWCUSTOMERPROJECTVIEW

AS

  SELECT OPPRTNTY.CUST_ACNT_NBR,

    OPPRTNTY.OPPRTNTY_ID,

    OPPRTNTY.EXT_OPPRTNTY_ID,

    OPPRTNTY.OPPRTNTY_NM,

    OPPRTNTY.OPPRTNTY_DSC,

    LISTAGG(PROJECT.PROJECT_NM, ', ') WITHIN GROUP (

  ORDER BY PROJECT.PROJECT_NM) AS SUB_PRODUCT,

    LISTAGG(BATCH_CLASS.BATCH_CLASS_NM, ', ') WITHIN GROUP (

  ORDER BY BATCH_CLASS.BATCH_CLASS_NM) AS SUB_PRODUCT2,

    --PROJECT.PROJECT_NM,

    --BATCH_CLASS.BATCH_CLASS_NM,

    COUNT(PROJECT.PROJECT_ID) AS cnt

  FROM OPPRTNTY

  INNER JOIN PROJECT

  ON OPPRTNTY.OPPRTNTY_ID = PROJECT.OPPRTNTY_ID

  INNER JOIN BATCH_CLASS

  ON BATCH_CLASS.BATCH_CLASS_ID = PROJECT.BATCH_CLASS_ID

  GROUP BY OPPRTNTY.CUST_ACNT_NBR,

    OPPRTNTY.OPPRTNTY_ID,

    OPPRTNTY.EXT_OPPRTNTY_ID,

    OPPRTNTY.OPPRTNTY_NM,

    OPPRTNTY.OPPRTNTY_DSC;

  --PROJECT.PROJECT_NM,

  --BATCH_CLASS.BATCH_CLASS_NM ;