Find out the agent based on the responsibility from a rule via function module

Dear Experts,

I have a rule and under the responsibility of this rule  purchase groups are maintained. I want to pick up the only those agents which are maintained under purchase group RU50. I have called the function module  - 'RH_GET_ACTORS' and passed the rule no in ACT_OBJECT , sy-datum and in table - ACTOR_CONTAINER, I have passed  EKGRP, 003, C, RU50 to get the agent - 'ABCD' which is maintained under the purchase group - RU50. But ACTOR_TAB is returning all the agent of this rule. It is not checking RU50. So kindly suggest how I will get that specific agent maintained under the Pr.Group - RU50.