How to find the parent form of a subform entry?

How to find the parent form of a subform entry?

Hello,

I created 2 forms (Main and Sub) in Creator. In the Main form, I add a subform field, pointing to the Sub form. When I add a new entry in Main form, and add 2 entries in the subform field, I see the 2 new entries in the Sub form. That's fine.

Now, from this Sub form, how can I find the "parent" or linked record in the Main form ? Is there a hidden field linking a record from the main field to the sub field ? How Zoho manages that, and how can I get advantage of this (may be in Deluge )?