How to addCustomFilter to Many-To-Many subgrid control in CRM 2013

I want to add Customer Filter to a Many-To-Many subgrid.

I tried to edit ribbon xml for 'Add Existing' Button. Then call JavaScript on the form. But the LookupObjects(...) always return null.

I tried to Xrm.Page.getControl("Categories").addCustomFilter. But error says 'addCustomFilter' method is not support

Anyone can help.

Thanks in advance.