Replication of Hierarchy & Groups of MDG-F Objects

Hi,

I have few questions on replication of Hirarchies & groups:

1. I want to replicate Group & Hierarchy ( PCTR & CCTR ). I have done the setup for PCTR & CCTR which is replicating successfully.I have introduced the IDOC of PCTRG in DRFIMG setup with message type COGRP6. But my replication is not happening.What is the missing link?

   2. I am creating PCTR via single processing & then release of Edition is replicating the PCTR. However, i am the using the collective Processing for              creating PCTRG & PCTRH along with the assignment of PCTR to it. But still my replication is not happening for PCTRG. This is the process that I am        following.Is this the correct approach or I should go for addition of Custom Profit Center Group attribute right from the Data Modelling- UI Config -SMT          Mapping?

   3. What is the Idoc for Hierarchy which I can configure?

   4. Can We replicate Hierarchy through IDOC?If Yes then How? If not then what is the alternative way to do it?

I would really appreciate you if you could provide me an answer or a hint.

Best Regards,

Kaustubh