Hi All,
After some more researching about this topic, I found that it depends on the logon instance of a user. If a user is logged on once via RFC and I call CRM_ORDER_MAINTAIN , then in the next call of this FM too , the function GROUP will retain the values as it's the property of the RFC Context.
Hence, this should work in repetitive calls of ORDER_MAINTAIN and then in the end when the user has entered all values in the order and press SAVE , I can save the order through RFC.
Lastly , I shall have to call "RFC_CONNECTION_CLOSE" to clear the RFC context.
/Hasan