Begin
-- create the pending area
dbms_resource_manager.create_pending_area();
END;
/
BEGIN
-- Create the consumer group
dbms_resource_manager.create_consumer_group(
    CONSUMER_GROUP=>'ONLINE_USERS_LIMITED_EXEC_TIME',
    COMMENT=>'This is the consumer group that has limited execution time per statement'
    );
END;
/

BEGIN
--  We need a consumer group that maps to the desired machine:
  dbms_resource_manager.set_consumer_group_mapping(
    attribute => dbms_resource_manager.client_machine,
    value => 'PAC\LR9XY7T8',
    consumer_group =>'ONLINE_USERS_LIMITED_EXEC_TIME'
  );
END;
/

BEGIN
  dbms_resource_manager.set_consumer_group_mapping(
    attribute => dbms_resource_manager.client_machine,
    value => 'LR9XY7T8',
    consumer_group =>'ONLINE_USERS_LIMITED_EXEC_TIME'
  );
END;
/

BEGIN
  -- Now create a resource plan:
  dbms_resource_manager.create_plan(
    PLAN=> 'LIMITED_EXEC_TIME',
    COMMENT=>'Kill statement after exceeding total execution time'
  );
END;
/
-- Now let's create a plan directive for that special user group , the plan will cancel the current SQL if it runs for more than 120 sec
-- You can define multiple directives depending on requirement

BEGIN
dbms_resource_manager.create_plan_directive(
    PLAN=> 'LIMITED_EXEC_TIME',
    GROUP_OR_SUBPLAN=>'ONLINE_USERS_LIMITED_EXEC_TIME',
    COMMENT=>'Kill statement after exceeding total execution time',
    SWITCH_GROUP=>'CANCEL_SQL',
    SWITCH_TIME=>60,
    SWITCH_ESTIMATE=>false
  );

  --Basically for each plan we need to define the plan directives for the OTHER_GROUPS also, what that means is determine limits for all other sessions other than those bound by the consumer group ONLINE_USERS_LIMITED_EXEC_TIME.

  dbms_resource_manager.create_plan_directive(
    PLAN=> 'LIMITED_EXEC_TIME',
    GROUP_OR_SUBPLAN=>'OTHER_GROUPS',
    COMMENT=>'leave others alone',
    CPU_P1=>100
  );
  END;
/


exec dbms_resource_manager.validate_pending_area(); 

exec dbms_resource_manager.submit_pending_area(); 

exec dbms_resource_manager.create_pending_area(); 

alter system set RESOURCE_MANAGER_PLAN='LIMITED_EXEC_TIME';


After this when i am verifying calls from machine, 'LR9XY7T8' they are belongs to the consumer group 'OTHER_GROUPS' and sql query not getting timed out within 60 seconds as mentioned.
 

exec dbms_resource_manager_privs.grant_switch_consumer_group('test','ONLINE_USERS_LIMITED_EXEC_TIME',false);
alter system set RESOURCE_MANAGER_PLAN='LIMITED_EXEC_TIME';

USERNAME                        RESOURCE_CONSUMER_GROUP
-----------                     ------------------------------
TEST                           ONLINE_USERS_LIMITED_EXEC_TIME 

But then i am trying to test a negative scenario . Rollbackk all the above change.
And i am putting machine name as 'ABCD' in 'set_consumer_group_mapping' which doesnot exists at all.

BEGIN
  dbms_resource_manager.set_consumer_group_mapping(
    attribute => dbms_resource_manager.client_machine,
    value => 'ABCD',
    consumer_group =>'ONLINE_USERS_LIMITED_EXEC_TIME'
  );
END;
/

in this case too, user 'test' belongs to the new defined consumer group , even if there is no machine exists as 'ABCD' in this LAN. changing 
the priority for 'client_machine' using DBMS_RESOURCE_MANAGER.SET_CONSUMER_GROUP_MAPPING_PRI is not helping me.

USERNAME                        RESOURCE_CONSUMER_GROUP
-----------                     ------------------------------
TEST                           ONLINE_USERS_LIMITED_EXEC_TIME