Disabling the PF functionality alone in Exchange 2013 DAG

Hello Team

We are in situation to disable the PF functionality alone in exchange 2013 DAG. The goal is to that the users should not expand the PF hierarchy in outlook or OWA

We did the below trouble shooting which is not help us. We made the below below parameter as false on both Primary hierarchy and secondary hierarchy 

by isssing the command Set-Mailbox -PublicFolder "PFMB01"  - IsExcludedFromServingHierarchy: False,  IsHierarchyReady:False

Even though we made it false , the end user "DefaultPublicFolderMailbox" is showing as some of the secondary PF mailbox

and we cannot null it  . i think the behavior is correct as its in DAG

if we can null the DefaultPublicFolderMailbox to end user, they can not able to expand the PF hierarchy in outlook.

please help