CREATE OR ALTER TRIGGER TBL_TEST_BD0 FOR TBL_TEST
ACTIVE BEFORE DELETE POSITION 0
AS
begin
  IF (CONDITION1) THEN EXCEPTION A1;
end

CREATE OR ALTER TRIGGER TBL_TEST_BD1 FOR TBL_TEST
ACTIVE BEFORE DELETE POSITION 1
AS
begin
  if (CONDITION2) then EXCEPTION A2;
end