CREATE TABLE TMP_TABLE (
    SESSION_ID  ID /* ID = INTEGER NOT NULL */,
    TMP_ID      ID /* ID = INTEGER NOT NULL */
);
CREATE INDEX TMP_TABLE_IDX1 ON TMP_TABLE (SESSION_ID);

CREATE GLOBAL TEMPORARY TABLE TBL
ON COMMIT PRESERVE ROWS   
AS SELECT * FROM SP_TREE1(:parent_tree1)

select * 
from table1 t1
       join tbl on t1.group_id=tbl.group_id

CREATE TABLE tablename AS SELECT ...

CREATE GLOBAL TEMPORARY TABLE TBL (GROUP_ID integer)
ON COMMIT PRESERVE ROWS;
COMMIT;

inert into TBL(GROUP_ID)
SELECT GROUP_ID FROM SP_TREE1(:parent_tree1);

select t1.* 
from table1 t1
       join tbl on t1.group_id=tbl.group_id;